Fix launch to require petrol for launching satellites

Fix launch to require petrol for launching satellites

launch_sat() failed to call msl_equip().  Change msl_equip() to take
the mission character as argument, because the old hardcoded 'p' isn't
appropriate for satellites.  Best fit for satellites is 'r' for
reconnaissance, but mission_pln_equip() doesn't accept that
(pln_equip() does).  Fix that as well.