many UT cases are broken due to "AttributeError: type object 'Route' has no attribute 'foreign_keys'"

eg. http://logs.openstack.org/24/518824/1/gate/openstack-tox-py27/6ea4c06/job-output.txt.gz

2017-11-11 07:19:32.914772 | ubuntu-xenial | {2} midonet.neutron.tests.unit.test_extension_taas.TestMidonetTaasCaseML2.test_delete_tap_service_error_delete_neutron_resource [0.865560s] ... ok
2017-11-11 07:19:32.931319 | ubuntu-xenial | INFO [alembic.runtime.migration] Running upgrade 24f28869838b -> 41b509d10b5e, VPNaaS endpoint groups
2017-11-11 07:19:32.947636 | ubuntu-xenial | add_router_interface failed: No details.
2017-11-11 07:19:32.947704 | ubuntu-xenial | Traceback (most recent call last):
2017-11-11 07:19:32.947748 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/api/v2/resource.py", line 98, in resource
2017-11-11 07:19:32.947775 | ubuntu-xenial | result = method(request=request, **args)
2017-11-11 07:19:32.947812 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 92, in wrapped
2017-11-11 07:19:32.947837 | ubuntu-xenial | setattr(e, '_RETRY_EXCEEDED', True)
2017-11-11 07:19:32.947889 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-11-11 07:19:32.947946 | ubuntu-xenial | self.force_reraise()
2017-11-11 07:19:32.948002 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-11-11 07:19:32.948029 | ubuntu-xenial | six.reraise(self.type_, self.value, self.tb)
2017-11-11 07:19:32.948086 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 88, in wrapped
2017-11-11 07:19:32.948117 | ubuntu-xenial | return f(*args, **kwargs)
2017-11-11 07:19:32.948169 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_db/api.py", line 150, in wrapper
2017-11-11 07:19:32.948191 | ubuntu-xenial | ectxt.value = e.inner_exc
2017-11-11 07:19:32.948259 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-11-11 07:19:32.948291 | ubuntu-xenial | self.force_reraise()
2017-11-11 07:19:32.948363 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-11-11 07:19:32.948393 | ubuntu-xenial | six.reraise(self.type_, self.value, self.tb)
2017-11-11 07:19:32.948444 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_db/api.py", line 138, in wrapper
2017-11-11 07:19:32.948466 | ubuntu-xenial | return f(*args, **kwargs)
2017-11-11 07:19:32.948504 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 127, in wrapped
2017-11-11 07:19:32.948533 | ubuntu-xenial | LOG.debug("Retry wrapper got retriable exception: %s", e)
2017-11-11 07:19:32.948586 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-11-11 07:19:32.948607 | ubuntu-xenial | self.force_reraise()
2017-11-11 07:19:32.948659 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-11-11 07:19:32.948686 | ubuntu-xenial | six.reraise(self.type_, self.value, self.tb)
2017-11-11 07:19:32.948723 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 123, in wrapped
2017-11-11 07:19:32.948746 | ubuntu-xenial | return f(*dup_args, **dup_kwargs)
2017-11-11 07:19:32.948786 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/api/v2/base.py", line 247, in _handle_action
2017-11-11 07:19:32.948817 | ubuntu-xenial | ret_value = getattr(self._plugin, name)(*arg_list, **kwargs)
2017-11-11 07:19:32.948867 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_log/helpers.py", line 67, in wrapper
2017-11-11 07:19:32.948890 | ubuntu-xenial | return method(*args, **kwargs)
2017-11-11 07:19:32.948927 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 162, in wrapped
2017-11-11 07:19:32.948950 | ubuntu-xenial | return method(*args, **kwargs)
2017-11-11 07:19:32.948988 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 92, in wrapped
2017-11-11 07:19:32.949012 | ubuntu-xenial | setattr(e, '_RETRY_EXCEEDED', True)
2017-11-11 07:19:32.949067 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-11-11 07:19:32.949089 | ubuntu-xenial | self.force_reraise()
2017-11-11 07:19:32.949142 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-11-11 07:19:32.949167 | ubuntu-xenial | six.reraise(self.type_, self.value, self.tb)
2017-11-11 07:19:32.949205 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 88, in wrapped
2017-11-11 07:19:32.949226 | ubuntu-xenial | return f(*args, **kwargs)
2017-11-11 07:19:32.949276 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_db/api.py", line 150, in wrapper
2017-11-11 07:19:32.949297 | ubuntu-xenial | ectxt.value = e.inner_exc
2017-11-11 07:19:32.949349 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-11-11 07:19:32.949368 | ubuntu-xenial | self.force_reraise()
2017-11-11 07:19:32.949427 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-11-11 07:19:32.949455 | ubuntu-xenial | six.reraise(self.type_, self.value, self.tb)
2017-11-11 07:19:32.949504 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_db/api.py", line 138, in wrapper
2017-11-11 07:19:32.949526 | ubuntu-xenial | return f(*args, **kwargs)
2017-11-11 07:19:32.949563 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 127, in wrapped
2017-11-11 07:19:32.949591 | ubuntu-xenial | LOG.debug("Retry wrapper got retriable exception: %s", e)
2017-11-11 07:19:32.949642 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-11-11 07:19:32.949662 | ubuntu-xenial | self.force_reraise()
2017-11-11 07:19:32.949715 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/networking-midonet/.tox/py27/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-11-11 07:19:32.949741 | ubuntu-xenial | six.reraise(self.type_, self.value, self.tb)
2017-11-11 07:19:32.949777 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 123, in wrapped
2017-11-11 07:19:32.949800 | ubuntu-xenial | return f(*dup_args, **dup_kwargs)
2017-11-11 07:19:32.949835 | ubuntu-xenial | File "midonet/neutron/services/l3/l3_midonet.py", line 181, in add_router_interface
2017-11-11 07:19:32.949859 | ubuntu-xenial | context, router_id, interface_info)
2017-11-11 07:19:32.949899 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/l3_db.py", line 1874, in add_router_interface
2017-11-11 07:19:32.949923 | ubuntu-xenial | context, router_id, interface_info)
2017-11-11 07:19:32.949960 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 162, in wrapped
2017-11-11 07:19:32.950283 | ubuntu-xenial | return method(*args, **kwargs)
2017-11-11 07:19:32.950337 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/l3_db.py", line 844, in add_router_interface
2017-11-11 07:19:32.950368 | ubuntu-xenial | context, router, interface_info['subnet_id'], device_owner)
2017-11-11 07:19:32.950423 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/l3_db.py", line 782, in _add_interface_by_subnet
2017-11-11 07:19:32.950463 | ubuntu-xenial | subnet['network_id'], [subnet])
2017-11-11 07:19:32.950511 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/l3_db.py", line 615, in _check_for_dup_router_subnets
2017-11-11 07:19:32.950532 | ubuntu-xenial | filters=id_filter)
2017-11-11 07:19:32.950569 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/api.py", line 162, in wrapped
2017-11-11 07:19:32.950592 | ubuntu-xenial | return method(*args, **kwargs)
2017-11-11 07:19:32.950687 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/db_base_plugin_v2.py", line 1023, in get_subnets
2017-11-11 07:19:32.951328 | ubuntu-xenial | marker, page_reverse)
2017-11-11 07:19:32.951383 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/db/db_base_plugin_common.py", line 282, in _get_subnets
2017-11-11 07:19:32.951403 | ubuntu-xenial | **filters)
2017-11-11 07:19:32.951444 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/objects/base.py", line 468, in get_objects
2017-11-11 07:19:32.951500 | ubuntu-xenial | return [cls._load_object(context, db_obj) for db_obj in db_objs]
2017-11-11 07:19:32.951563 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/objects/base.py", line 403, in _load_object
2017-11-11 07:19:32.951591 | ubuntu-xenial | obj.from_db_object(db_obj)
2017-11-11 07:19:32.951649 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/objects/subnet.py", line 250, in from_db_object
2017-11-11 07:19:32.951680 | ubuntu-xenial | super(Subnet, self).from_db_object(db_obj)
2017-11-11 07:19:32.951722 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/objects/base.py", line 347, in from_db_object
2017-11-11 07:19:32.951754 | ubuntu-xenial | self.load_synthetic_db_fields(db_obj)
2017-11-11 07:19:32.951838 | ubuntu-xenial | File "/home/zuul/src/git.openstack.org/openstack/neutron/neutron/objects/base.py", line 596, in load_synthetic_db_fields
2017-11-11 07:19:32.952042 | ubuntu-xenial | foreign_keys = objclass.foreign_keys.get(clsname)
2017-11-11 07:19:32.952080 | ubuntu-xenial | AttributeError: type object 'Route' has no attribute 'foreign_keys'