Add back --token-only for invocation compatibility
Add back --token-only for invocation compatibility

This unused option should remain so that scripts that
use it do not break. It is suppressed so it will not
appear in the help.

Closes-Bug:1250731

Change-Id: I1180d8797d1e4c79dba92952931311cce50a1d3f

tcpcloud/python-heatclient,varunarya10/python-heatclient,rdo-management/python-heatclient,jasondunsmore/python-heatclient,openstack/python-heatclient,metacloud/python-heatclient,jasondunsmore/python-heatclient,metacloud/python-heatclient,tcpcloud/python-heatclient,larsks/python-heatclient,rdo-management/python-heatclient,ecerulm/python-heatclient,varunarya10/python-heatclient,larsks/python-heatclient,ecerulm/python-heatclient