(svn r1607) -Fix: When deleting an order, the next pointer was not cleared,

resulting in some unusual behavoir from time to time

order_cmd.c

@@ -273,6 +273,7 @@ int32 CmdDeleteOrder(int x, int y, uint32 flags, uint32 vehicle_id, uint32 selec
 
 		/* Give the item free */
 		order->type = OT_NOTHING;
+		order->next = NULL;
 
 		u = GetFirstVehicleFromSharedList(v);
 		while (u != NULL) {
@@ -568,6 +569,7 @@ void BackupVehicleOrders(Vehicle *v, BackuppedOrders *bak)
 		}
 		/* End the list with an OT_NOTHING */
 		dest->type = OT_NOTHING;
+		dest->next = NULL;
 	}
 }