Improve the output when there is a functional error
Improve the output when there is a functional error

If solum sends an error or keystoneclient has an authentication
error don't print usage information.

Change-Id: I1e5aef0f4a2b69d0819d75dffb025e2cb47a60f7

ed-/python-solumclient,stackforge/python-solumclient,rackerlabs/arborlabs_client,ed-/python-solumclient,openstack/python-solumclient,rackerlabs/arborlabs_client,stackforge/python-solumclient