Updated openstack/openstack
Project: openstack/keystone  8187659ff4ba1c0dc4adecc547cfb0c2f11704ec
null
Use assertIsNone when comparing against None

Automatic enforcement of this rule is added in:
https://review.openstack.org/78119

bp more-code-style-automation

Change-Id: I3969d7595494d5df5bdb072234f2facc6000ab30