Handle federated tokens

Federated tokens don't include domains in the user object.
Keystoneclient should be able to estimate whether the token is a
federated one and, if so, don't expect user domain information.
In case of the federated token keystoneclient returns None in response
to user_domain_name and user_domain_id calls.

Co-Authored-By: Steve Martinelli <stevemar@ca.ibm.com>

Closes-Bug: #1346820
Change-Id: I3453275fa1b0a41b1c015b0c3a92895a77d69a41
Merge "Handle federated tokens"