Support v2 Keystone API in client
Support v2 Keystone API in client

Closes-Bug: #1349250

Change-Id: I85208a3dfc6b3485d295e90740535f93ae847207

StackStorm/python-mistralclient,StackStorm/python-mistralclient,openstack/python-mistralclient,openstack/python-mistralclient