v3 credential set always needs --user option
v3 credential set always needs --user option

Change-Id: Ieca76bb6ee2f328f4e33010623c25eb9c18e6952
Closes-Bug: #1372744

BjoernT/python-openstackclient,redhat-openstack/python-openstackclient,redhat-openstack/python-openstackclient,BjoernT/python-openstackclient,dtroyer/python-openstackclient,varunarya10/python-openstackclient,dtroyer/python-openstackclient,varunarya10/python-openstackclient,openstack/python-openstackclient,openstack/python-openstackclient