(svn r6516) -Fix r6513: killed warnings about two variables being used uninitialized

This is not even correct since it's set in if (a) and later used in another if (a), but GCC didn't detect that

depot_gui.c

@@ -301,7 +301,7 @@ enum {
 static int GetVehicleFromDepotWndPt(const Window *w, int x, int y, Vehicle **veh, GetDepotVehiclePtData *d)
 {
 	Vehicle **vl = WP(w, depot_d).vehicle_list;
-	uint xt, row, xm, ym;
+	uint xt, row, xm = 0, ym = 0;
 	int pos, skip = 0;
 
 	if (WP(w, depot_d).type == VEH_Train) {