Avoid returning stale token via auth_token property

The auth_ref token should take precedence over the user provided
token, since any call to authenticate() will update the auth_ref,
rendering the auth_token_from_user stale.

Change-Id: Ibc86dca840f4b8dd23856735616ee48a7b397fcd
Closes-Bug: #1244675
Merge "Avoid returning stale token via auth_token property"