unit tests: Don't mess with template retrospectively
unit tests: Don't mess with template retrospectively

In a couple of places we were modifying the template after creating the
stack with it, which is obviously not guaranteed to work.

Change-Id: I572cf6d7ac58392a9eb983ba8602481d0123c401

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