Update Havana/2013.2 refs to Icehouse/2014.1
Remove patch for rendering exception

This change removes a patch that was introduced so as to render properly
the exceptions as an WSGI response, since the change is now in Keystone.
Explicit import of '_'
Use correct API when getting the project

The get_project_by_name belongs to keystone.assignment.Manager and
not to keystone.identity.Manager.