Test utils dummy_context for tests that need one.

Change-Id: I3c54ec76a4d2bfd03cf60b70c422bc6269af01c9
Move url_for into heat_keystoneclient.

This allows faking of this call, and removes one instance of
accessing the encapsulated keystone client.

Change-Id: Iad2a9aaad2e9f1dc3cbeb509c822a61427f12817
Handle InstanceType change in Instance.handle_update

Make a resize API call against Nova if the InstanceType of an Instance
resource is change via a resource update.

Implements: blueprint instance-resize-update-stack
Change-Id: Ic4ee82edec842ee756b104a36dfef28bf3f89717
Merge "Test utils dummy_context for tests that need one."
Merge "Move url_for into heat_keystoneclient."
Merge remote branch 'upstream/master' into cloud-server
Remove _resize_server()

Change-Id: Ia829cdb381109e73d41e6d4c4ad691e879dfd528