Utilizes assertIsNone and assertIsNotNone
Utilizes assertIsNone and assertIsNotNone

Using assertEqual/assertNotEqual to test if an element
is or is not None is too python2.4.
Our unit testing framework supports assertIsNone and assertIsNotNone
which were created for these types of tests.

Change-Id: I29f915ae79bf4f8e9298c5de5d6087828fb0ca4f

varunarya10/oslo.utils,openstack/oslo.utils,magic0704/oslo.utils,dims/oslo.utils