Add missing metadefs for shutdown behavior

The following Nova patch adds support for graceful shutdown
of a guest VM and allows setting timeout properties on images.
The properties should be updated in the Metadata Definitions catalog.

https://review.openstack.org/#/c/68942/

Change-Id: I58145d9d0114b3932b63263ea123c4662146d14b
Closes-bug: 1368036
(cherry picked from commit 5fcb3aa2e35e9af17cb8be9e24c6613626036f2b)
Merge "Add missing metadefs for shutdown behavior" into proposed/juno