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: I954b45202073d7daa28d0240c0fd005b08b742fb
Closes-Bug:#1280522

openstack/magnum,ArchiFleKs/magnum,openstack/magnum,ArchiFleKs/magnum