Updated openstack/openstack
Project: openstack/cliff  4378c26b8eed103f70b94e2b09ec43de5b59af8c

Fix wrong method name assert_called_once

There isn't method assert_called_once, and it doesn't really
check anything. We'd better check mock.called directly.

Change-Id: Iffbaa176c3efd41084a655adcbbb0821d8ad496d