Comment 54 for bug 1323658

If there is something in here related to vif plugging callbacks with neutron and we're not waiting long enough, we could add some logging in resize_instance and _post_live_migration like was added to _delete_instance here:

https://github.com/openstack/nova/commit/272aca6926f50b584dab77fb2d1c29fc8bdbdb9e