Updated openstack/openstack
Project: openstack/heat  3c2256ab96da752f604ecc8c34196f900f521077

Support loading constraints as stevedore extensions

This still maintains support for the existing mechanism
but moves the in tree constraints to using stevedore.

part of blueprint stevedore-plugins
Change-Id: I86907e6518281083a508f840269d79dfa3875e9a