don't repair flying vtols

[gantsevdenis]

but still can repair them when they land.

[KJeff01]

Not sure if anyone cares but it will mean you won't be able to repair any transporter unit as they can't land on VTOL pads.

bool isFlying(const DROID *psDroid)
{
	return (asPropulsionStats + psDroid->asBits[COMP_PROPULSION])->propulsionType == PROPULSION_TYPE_LIFT
		   && (psDroid->sMove.Status != MOVEINACTIVE || isTransporter(psDroid));
}

In which case a !isTransporter() can be put around these changes to avoid that.

[gantsevdenis]

closing because #2840