Send create.end notification even if instance is deleted

There was an unprotected instance.save() call which could raise an
exception and bypass a create.end notification.  This adds a try/except
block around that call with appropriate handling of the exception.

Change-Id: I308ee84f6ab2bb37ef6570ff896017615a5bf746
Closes-bug: #1358795
Merge "Send create.end notification even if instance is deleted"