We provide hooks for pre-create and pre-update, but not for pre-delete. Such a hook would allow users to make specific actions when a resource is deleted, like deregistration with external systems, and will provide the ability to validate deletion of critical elements. Blueprint: https://blueprints.launchpad.net/heat/+spec/pre-delete-hook
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHEA-2016-1597.html