Fix Coop Bug in RHANGAR1 when friendly fire was off

In RHANGAR1 the turret didn't blow up the ceiling when friendly fire
was off, because in ClientTeam() both entities were set to "" (no team),
but OnSameTeam() just did a strcmp() instead of checking this special
case (no team).
We check this now and thus it works. Hooray.

The savegame table entry for this function was invalid, but it doesn't
need to be saved anyway, so I just deleted it from the table.