Correctly handle auth_url/token authentication

Previously the client assumed that if a user passed a token then this
token should be used for everything. This assumption is correct for the
endpoint/token case but not in the auth_url/token case where you will
want to fetch a new token. This is needed in the case where you want to
use an existing token to fetch a token that is re-scoped or activate a
trust.

There are still problems such as if you use auth_url/token
authentication then when the token expires it will try to refresh it,
but authenticating with a token will not extend the token expiry.

Closes-Bug: #1257541
Change-Id: I1c35600ca5437da44071dcea5361bfb42f6b72a3
Merge "Correctly handle auth_url/token authentication"