Fix wrong variable used in battery button

Author: cesarBLG

Source/Orts.Simulation/Simulation/RollingStocks/MSTSLocomotive.cs

@@ -5208,7 +5208,7 @@ public virtual float GetDataOf(CabViewControl cvc)
                     break;
 
                 case CABViewControlTypes.ORTS_BATTERY_SWITCH_COMMAND_BUTTON_OPEN:
-                    data = LocomotivePowerSupply.BatterySwitch.CommandButtonOn ? 1 : 0;
+                    data = LocomotivePowerSupply.BatterySwitch.CommandButtonOff ? 1 : 0;
                     break;
 
                 case CABViewControlTypes.ORTS_BATTERY_SWITCH_ON: