tempest cleanup should use keystone v3 client

tempest cleanup returns an error when it's initializing a saved
state, because it uses already deprecated v2 client.
The patch makes tempest cleanup use keystone role v3 client.

Related-prod: PROD-00000
Closes-Bug: #1788561

Change-Id: Id607dec012ce48af6d4c7ee263a90c3ea2e1799c
(cherry picked from commit e4a709ebe8c12e95829897416d3132670b9654e8)
1 file changed