(svn r6356) -Fix: FS#263 planes come out of hangar and drive back into hangar

Now all vehicles are serviced when it's time for service and they are in a depot
   This will avoid the goto depot order from ever showing up when in a depot

ship_cmd.c

@@ -112,6 +112,11 @@ static void CheckIfShipNeedsService(Vehicle *v)
 
 	if (_patches.gotodepot && VehicleHasDepotOrders(v)) return;
 
+	if (IsShipInDepot(v)) {
+		VehicleServiceInDepot(v);
+		return;
+	}
+
 	depot = FindClosestShipDepot(v);
 
 	if (depot == NULL || DistanceManhattan(v->tile, depot->xy) > 12) {