Remove auth_token condition in clients

* Removed useless auth_token condition in clients
since we already have a condition in auth_token getter that returns
"self.context.auth_token or keystone().auth_token", keystoneclient
will raise an "AuthorizationFailure: A username and password or token
 is required" and the error message of the condition won't be shown.
* Added unit tests with no auth_token and with heat client cached

Closes-Bug: #1293806
Change-Id: Ic9ad0e60c09be1ac923f7ef8b669733d7e9c896e
Updated from global requirements

Change-Id: I3791a77a1ff44bc6d63a0cf94b5b32b6df9a06d6
Merge "Remove auth_token condition in clients"
Merge "Updated from global requirements"