Remove the usecases from environment.py as they are in the docs
Remove the usecases from environment.py as they are in the docs

Change-Id: Ibe0b55663a62b4a68f1478d254f1333a56514c38

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