Add descriptive message for auth failture

If we fail to auth in tests we display now
message that keystone is unavailable. It is a
liitle bit confuse. So add verification
that if we fail with 401 unauth dispaly
more descriptive message

Change-Id: I3846e266973fdfc3009b7df7382a57296c1c4c5c
Merge "Add descriptive message for auth failture"