A few major-upgrade issues

This commit does the following:
1. We now explicitly disable/stop and then remove the resources that are
   moving to systemd. We do this because we want to make sure they are all
   stopped before doing a yum upgrade, which otherwise would take ages due
   to rabbitmq and galera being down. It is best if we do this via pcs
   while we do the HA Full -> HA NG migration because it is simpler to make
   sure all the services are stopped at that stage. For extra safety we can
   still do a check by hand. By doing it via pacemaker we have the
   guarantee that all the migrated services are down already when we stop
   the cluster (which happens to be a syncronization point between all
   controller nodes). That way we can be certain that they are all down on
   all nodes before starting the yum upgrade process.

2. We actually need to start the systemd services in
   major_upgrade_controller_pacemaker_2.sh and not stop them.

3. We need to use the proper bash variable name

4. Use is_bootstrap_node everywhere to make the code more consistent

Change-Id: Ic565c781b80357bed9483df45a4a94ec0423487c
Closes-Bug: #1627490