Scheduled dispatch: Fixup start dates when changing game date

src/date.cpp

@@ -231,6 +231,7 @@ static void OnNewYear()
 		_date -= days_this_year;
 		for (Vehicle *v : Vehicle::Iterate()) v->date_of_last_service -= days_this_year;
 		for (LinkGraph *lg : LinkGraph::Iterate()) lg->ShiftDates(-days_this_year);
+		ShiftOrderDates(-days_this_year);
 
 		/* Because the _date wraps here, and text-messages expire by game-days, we have to clean out
 		 *  all of them if the date is set back, else those messages will hang for ever */