Start mongod before calling ceilometer-dbsync

Start mongod before calling ceilometer-dbsync

Currently we in major_upgrade_controller_pacemaker_2.sh we are calling
ceilometer-dbsync before mongod is actually started (only galera is
started at this point). This will make the dbsync hang indefinitely
until the heat stack times out.

Now this approach should be okay, but do note that when we start mongod
via systemctl we are not guaranteed that it will be up on all nodes
before we call ceilometer-dbsync. This *should* be okay because
ceilometer-dbsync keeps retrying and eventually one of the nodes will
be available. A completely clean fix here would be to add another
step in heat to have the guarantee that all mongo servers are up and
running before the dbsync call.

Change-Id: I10c960b1e0efdeb1e55d77c25aebf1e3e67f17ca
Closes-Bug: #1627453