packaging: updated user prompts for stopping ovirt-engine service during setup

* If the engine service is in state not running, and only in this
  state, avoid to ask for stopping the service.
  The script doesn't check for service up and running, avoiding a
  regression on RHBZ #837812.

* Avoid to stop the engine service if already stopped and not configured.

Change-Id: I01da6e908a9f396bf4211afe863475d9fc2093be
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=896694
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>