No network connectivity inside VMs after host reboot

[Roman Podoliaka]

When a host is rebooted and resume_guests_state_on_host_boot is set to True, it may happen (although, it's an edge case) that nova-compute starts before OVS finishes initialization of all created bridges, and thus we'll see the following error when creating an ovs vif port:

2016-01-05 02:57:57.970 11932 ERROR nova.network.linux_net [req-e5b5ba37-fff7-4b41-9dda-00c2c54a8e22 - - - - -] Unable to execute ['ovs-vsctl', '--timeout=120', '--', '--if-exists', 'del-port', u'qvob2efeceb-e4', '--', 'add-port', u'br-int', u'qvob2efeceb-e4', '--', 'set', 'Interface', u'qvob2efeceb-e4', u'external-ids:iface-id=b2efeceb-e46f-41f5-a1b2-add7f5dd7a80', 'external-ids:iface-status=active', u'external-ids:attached-mac=fa:16:3e:34:91:87', 'external-ids:vm-uuid=50118e0e-e104-4cc0-b154-b0dcdaef0494']. Exception: Unexpected error while running command.
Command: sudo nova-rootwrap /etc/nova/rootwrap.conf ovs-vsctl --timeout=120 -- --if-exists del-port qvob2efeceb-e4 -- add-port br-int qvob2efeceb-e4 -- set Interface qvob2efeceb-e4 external-ids:iface-id=b2efeceb-e46f-41f5-a1b2-add7f5dd7a80 external-ids:iface-status=active external-ids:attached-mac=fa:16:3e:34:91:87 external-ids:vm-uuid=50118e0e-e104-4cc0-b154-b0dcdaef0494
Exit code: 1
Stdout: u''
Stderr: u'ovs-vsctl: no bridge named br-int\n'

An instance will be booted successfully, but there will be no network connectivity inside the VM.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/265973

[OpenStack Infra (hudson-openstack)]

Change abandoned by Michael Still (<email address hidden>) on branch: master
Review: https://review.openstack.org/265973
Reason: This code hasn't been updated in a long time, and is in merge conflict. I am going to abandon this review, but feel free to restore it if you're still working on this.