The majority of the mocks on keystoneclient are not needed. Instead we
use the fixtures that keystoneclient provides to create well formed
responses and use requests_mock to stub out those values when accessed.
This is a closer to real usage pattern and the way that most client
projects are now handling keystoneclient auth.
Change-Id: I294aca1d11c9c5cfb4b82ad16476af4000efee1c