Updated openstack/openstack
Project: openstack/heat  b74eb6735ca9c1654d50e6640b026a1266058c32

Add missing DeprecationWarning category to warning

This is a deprecation warning but it lacks the category specifier
for DeprecationWarning.

Change-Id: I4f31c2cd64b94564ff53d944cae36bff472491d4