TestNetworkQuotaBasic tearDownClass fails while deleting port

Port delete fails and lead to this stacktrace:

ft4.1: tearDownClass (tempest.scenario.test_network_quotas.TestNetworkQuotaBasic)_StringException: Traceback (most recent call last):
  File "tempest/scenario/manager.py", line 248, in tearDownClass
    thing.delete()
  File "tempest/api/network/common.py", line 96, in delete
    self.client.delete_port(self.id)
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 111, in with_params
    ret = self.function(instance, *args, **kwargs)
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 326, in delete_port
    return self.delete(self.port_path % (port))
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 1232, in delete
    headers=headers, params=params)
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 1221, in retry_request
    headers=headers, params=params)
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 1164, in do_request
    self._handle_fault_response(status_code, replybody)
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 1134, in _handle_fault_response
    exception_handler_v20(status_code, des_error_body)
  File "/opt/stack/new/python-neutronclient/neutronclient/v2_0/client.py", line 84, in exception_handler_v20
    message=error_dict)
NeutronClientException: Request Failed: internal server error while processing your request.

Neutron's log reveal this nasty trace:

[req-30fa1925-067f-4320-883c-a95b3f0630b8 885beea8ad4e4d77a4c69eee7303f28b f1c02eacabf946abaa3eff289e0df1a9] delete failed
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource Traceback (most recent call last):
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/opt/stack/new/neutron/neutron/api/v2/resource.py", line 84, in resource
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource result = method(request=request, **args)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/opt/stack/new/neutron/neutron/api/v2/base.py", line 432, in delete
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource obj_deleter(request.context, id, **kwargs)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/opt/stack/new/neutron/neutron/plugins/ml2/plugin.py", line 657, in delete_port
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource super(Ml2Plugin, self).delete_port(context, id)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/opt/stack/new/neutron/neutron/db/db_base_plugin_v2.py", line 1403, in delete_port
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource self._delete_port(context, id)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/opt/stack/new/neutron/neutron/db/db_base_plugin_v2.py", line 1423, in _delete_port
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource port = query.with_lockmode('update').one()
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2184, in one
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource ret = list(self)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2227, in __iter__
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource return self._execute_and_instances(context)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2242, in _execute_and_instances
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource result = conn.execute(querycontext.statement, self._params)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1449, in execute
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource params)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1584, in _execute_clauseelement
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource compiled_sql, distilled_params
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1698, in _execute_context
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource context)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1691, in _execute_context
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 331, in do_execute
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource cursor.execute(statement, parameters)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 174, in execute
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource self.errorhandler(self, exc, value)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource File "/usr/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource raise errorclass, errorvalue
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource OperationalError: (OperationalError) (1205, 'Lock wait timeout exceeded; try restarting transaction') 'SELECT ports.tenant_id AS ports_tenant_id, ports.id AS ports_id, ports.name AS ports_name, ports.network_id AS ports_network_id, ports.mac_address AS ports_mac_address, ports.admin_state_up AS ports_admin_state_up, ports.status AS ports_status, ports.device_id AS ports_device_id, ports.device_owner AS ports_device_owner \nFROM ports \nWHERE ports.id = %s FOR UPDATE' ('7bd9b18d-47f3-4a57-8cbe-63c800a0c6fb',)
2013-11-23 02:57:41.578 3524 TRACE neutron.api.v2.resource