Use keystoneauth instead of keystoneclient

Use keystoneauth instead of keystoneclient

keystoneauth was split out last cycle as a library specifically to deal
with doing auth functions so that people who do not need to do keystone
CRUD operations can just consume only the auth session parts. As part
of modernizing keystone interactions, use keystoneauth instead of
keystoneclient.

Depends-On: I1f754a9a949ef92f4e427a91bbd1b1e73e86c8c4
Change-Id: Ia6fb7d8bb07d3101cf1b1afc318f3dcac0a37afc