Make 'heat help' show a list of commands
Make 'heat help' show a list of commands

Previously we just printed an error message about not specifying a command
to get help about, and no hint about how to work out which commands even
existed.

Signed-off-by: Zane Bitter <1899fff8e7db19a598ee9d835aa1a232f82ea264@redhat.com>

takeshineshiro/heat,ntt-sic/heat,rh-s/heat,redhat-openstack/heat,cwolferh/heat-scratch,steveb/heat,openstack/heat-cfntools,Triv90/Heat,Triv90/Heat,steveb/heat-cfntools,takeshineshiro/heat,ntt-sic/heat,pratikmallya/heat,jasondunsmore/heat,openstack/heat,NeCTAR-RC/heat,bbandaru/heat-cfntools,dims/heat,Triv90/Heat,gonzolino/heat,dragorosson/heat,miguelgrinberg/heat,rdo-management/heat,sdake/heat-jeos,gonzolino/heat,cryptickp/heat,maestro-hybrid-cloud/heat,pshchelo/heat,cryptickp/heat,redhat-openstack/heat,JioCloud/heat,cwolferh/heat-scratch,dragorosson/heat,pratikmallya/heat,rickerc/heat_audit,noironetworks/heat,varunarya10/heat,rickerc/heat_audit,jasondunsmore/heat,NeCTAR-RC/heat,varunarya10/heat,rdo-management/heat,miguelgrinberg/heat,maestro-hybrid-cloud/heat,openstack/heat,noironetworks/heat,rh-s/heat,steveb/heat-cfntools,citrix-openstack-build/heat,dims/heat,JioCloud/heat,citrix-openstack-build/heat,pshchelo/heat,steveb/heat,srznew/heat,srznew/heat