Fix conductor's object change detection
Fix conductor's object change detection

Conductor was doing a copy.copy() on the inbound object to later
detect changes that should be sent back to the caller. This does not
copy things like Instance.system_metadata and thus is incapable of
properly detecting changes that should be tracked.

This patch makes conductor use obj_clone(), and imports Chris
Behrens' __deepcopy__ fix for objects so that deepcopy works.

Closes-bug: #1237102
Change-Id: I46ae8b0694dc31a90c1a5cdf76757d877877f072

citrix-openstack-build/oslo.versionedobjects,openstack/oslo.versionedobjects