(svn r21120) -Fix (r21096): Use the engine max speed value instead of the savegame value, as the latter could be stored in old units in old savegames.

src/aircraft_cmd.cpp

@@ -544,7 +544,7 @@ void UpdateAircraftCache(Aircraft *v)
 		v->vcache.cached_max_speed = max_speed;
 	} else {
 		/* Use the default max speed of the vehicle. */
-		v->vcache.cached_max_speed = v->max_speed;
+		v->vcache.cached_max_speed = AircraftVehInfo(v->engine_type)->max_speed;
 	}
 }