Use keystone sessions for v1 client

This removes the code for checking if the service catalog has a version part in
the url or not aka /v1 and removing it as it's handled by the underlying
ksclient code in sessions. It also removes old authentication code.

Change-Id: I04109a935d7d94518c7dab05122a64ef37190d44
Merge "Use keystone sessions for v1 client"