Stop stack updates from exceeding resource limit

Previous patches raise an error when a newly created stack would exceed
the limit. This one applies the same logic during an update. Note that
nested stack updates will be handled in another patch.

Change-Id: Ic5d32501f582640cb77629b902c32c8cb9c20b42
Partial-Bug: #1215100
Merge "Stop stack updates from exceeding resource limit"