Add missing constraints in yum_update.sh

Add missing constraints in yum_update.sh

Some missing pacemaker constraints were added in the following commits:

https://review.openstack.org/#/c/219770/
https://review.openstack.org/#/c/219665/
https://review.openstack.org/#/c/218931/
https://review.openstack.org/#/c/218930/

Overclouds that were deployed prior to these constraints being added to
tripleo-heat-templates still have the constraints missing. During an
update, stopping and starting the cluster can fail without these
constraints in place.  As a workaround, conditionally add these
contraints in yum_update.sh so that we're sure they're always present
before updating.

Change-Id: Id46c85dbbe5e85d362279661091b17ce1b697fe0