Update template paths for environment-mapped TemplateResources
Update template paths for environment-mapped TemplateResources

When updating a template resource, we weren't taking into account the
possibility that the new environment could be mapping the resource to a
different template path. This change ensures we recalculate the template
name from the new environment before reloading the template during an
update.

Change-Id: I5f84f6fd60925d3dba0b8e8dec867657c8c5c9ef
Closes-Bug: #1452534

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