Using assertIsNone() is preferred over assertEqual()
Using assertIsNone() is preferred over assertEqual()

Following OpenStack Style Guidelines:
http://docs.openstack.org/developer/hacking/#unit-tests-and-assertraises

[H203] Unit test assertions tend to give better messages for more specific assertions.
As a result, assertIsNone(...) is preferred over assertEqual(None, ...)

Change-Id: Id34fb0851d698ed9c1c77cbb230f32aa21678c4e

openstack/ironic-lib,NaohiroTamura/ironic-lib