Comment 2 for bug 1349369

Seeing this in Nova logs:

<178>Jul 28 10:46:34 node-2 nova-manage 2014-07-28 10:46:34.996 17815 CRITICAL nova [req-ccd28c6a-c224-4b8c-8f98-3b5dbd30b9a2 None] DuplicateVlan: Detected existing vlan with id 103
2014-07-28 10:46:34.996 17815 TRACE nova Traceback (most recent call last):
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/bin/nova-manage", line 10, in <module>
2014-07-28 10:46:34.996 17815 TRACE nova sys.exit(main())
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/cmd/manage.py", line 1376, in main
2014-07-28 10:46:34.996 17815 TRACE nova ret = fn(*fn_args, **fn_kwargs)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/cmd/manage.py", line 530, in create
2014-07-28 10:46:34.996 17815 TRACE nova net_manager.create_networks(context.get_admin_context(), **kwargs)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/network/manager.py", line 1865, in create_networks
2014-07-28 10:46:34.996 17815 TRACE nova self, context, vpn=True, **kwargs)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/network/manager.py", line 1094, in create_networks
2014-07-28 10:46:34.996 17815 TRACE nova return self._do_create_networks(context, **kwargs)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/network/manager.py", line 1232, in _do_create_networks
2014-07-28 10:46:34.996 17815 TRACE nova net.create()
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/objects/base.py", line 151, in wrapper
2014-07-28 10:46:34.996 17815 TRACE nova return fn(self, ctxt, *args, **kwargs)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/objects/network.py", line 131, in create
2014-07-28 10:46:34.996 17815 TRACE nova db_network = db.network_create_safe(context, updates)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/db/api.py", line 929, in network_create_safe
2014-07-28 10:46:34.996 17815 TRACE nova return IMPL.network_create_safe(context, values)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/db/sqlalchemy/api.py", line 146, in wrapper
2014-07-28 10:46:34.996 17815 TRACE nova return f(*args, **kwargs)
2014-07-28 10:46:34.996 17815 TRACE nova File "/usr/lib/python2.6/site-packages/nova/db/sqlalchemy/api.py", line 2519, in network_create_safe
2014-07-28 10:46:34.996 17815 TRACE nova raise exception.DuplicateVlan(vlan=values['vlan'])
2014-07-28 10:46:34.996 17815 TRACE nova DuplicateVlan: Detected existing vlan with id 103
2014-07-28 10:46:34.996 17815 TRACE nova