Update unit test case for Keystone client plug-in for service
Update unit test case for Keystone client plug-in for service

Updates required unit test cases for the keystone service
in the keystone client plug-in, with recent review comments
addressed in other keystone client plugin test cases.

Change-Id: Iabb176cf8f718d9eae4b4156979253085603424a
Related-Bug: #1463267

noironetworks/heat,steveb/heat,cwolferh/heat-scratch,srznew/heat,takeshineshiro/heat,steveb/heat,dims/heat,gonzolino/heat,pratikmallya/heat,cryptickp/heat,miguelgrinberg/heat,jasondunsmore/heat,dragorosson/heat,cryptickp/heat,miguelgrinberg/heat,jasondunsmore/heat,openstack/heat,maestro-hybrid-cloud/heat,openstack/heat,dims/heat,cwolferh/heat-scratch,rh-s/heat,gonzolino/heat,pratikmallya/heat,noironetworks/heat,dragorosson/heat,takeshineshiro/heat,srznew/heat,maestro-hybrid-cloud/heat,rh-s/heat