kombu classnotfound in stable/essex branch

I'm using the stable/essex branch on ubuntu 11.10
Yersterday, I updated my code, and an error appears when I restarted nova-compute or nova-scheduler :
2012-05-21 16:15:37 DEBUG nova.utils [req-b0de5796-04dc-4621-9418-5de025406e7d None None] backend <module 'nova.db.sqlalchemy.api' from '/usr/local/src/nova/nova/db/sqlalchemy/api.pyc'> from (pid=15990) __get_backend /usr/local/src/nova/nova/utils.py:658
2012-05-21 16:15:37 DEBUG nova.utils [req-b0de5796-04dc-4621-9418-5de025406e7d None None] Inner Exception: 'module' object has no attribute 'impl_kombu' from (pid=15990) import_class /usr/local/src/nova/nova/utils.py:78
2012-05-21 16:15:37 CRITICAL nova [-] Class impl_kombu could not be found: 'module' object has no attribute 'impl_kombu'
2012-05-21 16:15:37 TRACE nova Traceback (most recent call last):
2012-05-21 16:15:37 TRACE nova File "/usr/local/bin/nova-scheduler", line 7, in <module>
2012-05-21 16:15:37 TRACE nova execfile(__file__)
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/bin/nova-scheduler", line 51, in <module>
2012-05-21 16:15:37 TRACE nova service.wait()
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/service.py", line 413, in wait
2012-05-21 16:15:37 TRACE nova _launcher.wait()
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/service.py", line 131, in wait
2012-05-21 16:15:37 TRACE nova service.wait()
2012-05-21 16:15:37 TRACE nova File "/usr/local/lib/python2.7/dist-packages/eventlet-0.9.16-py2.7.egg/eventlet/greenthread.py", line 166, in wait
2012-05-21 16:15:37 TRACE nova return self._exit_event.wait()
2012-05-21 16:15:37 TRACE nova File "/usr/local/lib/python2.7/dist-packages/eventlet-0.9.16-py2.7.egg/eventlet/event.py", line 116, in wait
2012-05-21 16:15:37 TRACE nova return hubs.get_hub().switch()
2012-05-21 16:15:37 TRACE nova File "/usr/local/lib/python2.7/dist-packages/eventlet-0.9.16-py2.7.egg/eventlet/hubs/hub.py", line 177, in switch
2012-05-21 16:15:37 TRACE nova return self.greenlet.switch()
2012-05-21 16:15:37 TRACE nova File "/usr/local/lib/python2.7/dist-packages/eventlet-0.9.16-py2.7.egg/eventlet/greenthread.py", line 192, in main
2012-05-21 16:15:37 TRACE nova result = function(*args, **kwargs)
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/service.py", line 101, in run_server
2012-05-21 16:15:37 TRACE nova server.start()
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/service.py", line 176, in start
2012-05-21 16:15:37 TRACE nova self.conn = rpc.create_connection(new=True)
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/rpc/__init__.py", line 46, in create_connection
2012-05-21 16:15:37 TRACE nova return _get_impl().create_connection(new=new)
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/rpc/__init__.py", line 201, in _get_impl
2012-05-21 16:15:37 TRACE nova _RPCIMPL = utils.import_object(FLAGS.rpc_backend)
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/utils.py", line 88, in import_object
2012-05-21 16:15:37 TRACE nova cls = import_class(import_str)
2012-05-21 16:15:37 TRACE nova File "/usr/local/src/nova/nova/utils.py", line 79, in import_class
2012-05-21 16:15:37 TRACE nova raise exception.ClassNotFound(class_name=class_str, exception=exc)
2012-05-21 16:15:37 TRACE nova ClassNotFound: Class impl_kombu could not be found: 'module' object has no attribute 'impl_kombu'

basically, the kombu module gets an error when it is loaded, it can't find the "loads" module in the anyjson package. The issue that the dist-package python directory has two anyjson egg-info directory :

anyjson-0.2.4-py2.7.egg/ and anyjson-0.3.1.egg-info/

anyjson-0.3.1should be used, it has loads module, but anyjson-0.2.4 is loaded.
The workaround is to erase anyjson-0.2.4-py2.7.egg/