Updated openstack/openstack
Project: openstack/nova  b74b292db2cdc4714815c868ddc1c1eb76afca70

Fix wrong method name assert_called_once

There isn't method assert_called_once, and it doesn't really
check anything.  we use assertTrue(mock.called) instead.

Change-Id: Ibea0bbe5346220d59eea3b551b7548a3beaa5a6e