mx nodes need to disable soledad service
Because leap-mx depends on soledad-server, that package gets installed and is configured to start on boot.
This fails with an ugly traceback because the right stuff (like certs) aren't installed on mx nodes because they aren't soledad nodes.
So we need to disable the startup on mx nodes.
(from redmine: created on 2013-08-14, closed on 2013-08-14)