Prevent any property change from replacing OS::Nova::Server
Prevent any property change from replacing OS::Nova::Server

This change ensures that any property change in an OS::Nova::Server
resource will not result in the server being replaced. This is a more
complete approach to only protecting servers from changes to the
user_data property - upgrades testing have also shown replacement issues
with other properties such as scheduler_hints.

Change-Id: I6127ca9c3abb57c025df7d039c03bb7e64efad2c
Related-Bug: #1539541

openstack/tripleo-common,openstack/tripleo-common