Remove unused versions define in template_format.py
Remove unused versions define in template_format.py

Remove unused 'HEAT_VERSIONS' and 'CFN_VERSIONS' define in
template_format.py.

Change-Id: Icb6920fa481259868b6bf2feaab9859a13c59467

steveb/heat,steveb/heat,srznew/heat,openstack/heat,gonzolino/heat,cwolferh/heat-scratch,dims/heat,rh-s/heat,maestro-hybrid-cloud/heat,dragorosson/heat,rh-s/heat,redhat-openstack/heat,pshchelo/heat,miguelgrinberg/heat,noironetworks/heat,cryptickp/heat,pratikmallya/heat,cwolferh/heat-scratch,rdo-management/heat,dragorosson/heat,pratikmallya/heat,maestro-hybrid-cloud/heat,pshchelo/heat,takeshineshiro/heat,rdo-management/heat,noironetworks/heat,openstack/heat,NeCTAR-RC/heat,jasondunsmore/heat,miguelgrinberg/heat,dims/heat,srznew/heat,takeshineshiro/heat,cryptickp/heat,NeCTAR-RC/heat,jasondunsmore/heat,redhat-openstack/heat,gonzolino/heat