Replace assertEqual(None, *) with assertIsNone in tests
Replace assertEqual(None, *) with assertIsNone in tests

Replace assertEqual(None, *) with assertIsNone in tests to have
more clear messages in case of failure.

Change-Id: Ic2dca04e7cdd4f837c42b39dd1ce37604c8f101b
Closes-bug: #1280522

openstack/heat-cfntools