VehicleTypes Inside OpenTopped=yes Ignore AlternateFLHX

A passenger of type [VehicleTypes] that is placed into a transport of type [VehicleTypes] with OpenTopped=Yes can fire out, but that passenger ignores the AlternateFLHX artmd.ini entries of that transport.

To reproduce, perform the following:

    1. Change the SizeLimit of Battle Fortress to 5.
    2. Start a new game and build a Battle Fortress and a IFV.
    3. Put the IFV into the Battle Fortress.
    4. Observe that the IFV can fire out, but the projectiles ignore the
       locations as defined by the AlternateFLHX artmd.ini entries of the Battle
       Fortress.

The correct behaviour is that the IFV should not ignore the AlternateFLHX artmd.ini entries of the Battle Fortress.