Move auth_token tests not requiring v2/v3 to new class
Move auth_token tests not requiring v2/v3 to new class

The tests in CommonAuthTokenMiddlewareTest run for both v2 and v3
tokens, but contained tests that weren't affected by the token
version.

The tests that aren't affected by the token version are now in
their own class.

Change-Id: I0e8aecafcd8e0da262dded48a612c84b1629d953

varunarya10/keystonemiddleware