End of choose does not kill choose sign for road vehicle

[poppo]

In rail_vehicle_t::is_choose_signal_clear(), we check end_of_choose signal on the route t o the next stop, then find route if no end of choose sign on the route. If the sign on the route, choose signal is killed and treated as normal signal.

However, road_vehicle_t::choose_route() does not have such end_of_choose signal find calculation. so, if other car stop at the busstop, the road vehicle stop at the choose sign and try to find empty halt tiles even if end_of_choose is on the way.

So, I think we should check end_of_choose on the way like rail_vehicle_t::is_choose_signal_clear() and return earlier if there is a sign on the way to the stop.

[prissi]

Sounds reasonable

[prissi]

Comitted in r12148