Remove some dead code from UOG.

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -57,7 +57,6 @@ namespace OpenRA.Traits
     public interface IValidateOrder { bool OrderValidation(OrderManager orderManager, World world, int clientId, Order order); }
     public interface IOrderCursor { string CursorForOrder(Actor self, Order order); }
     public interface IOrderVoice { string VoicePhraseForOrder(Actor self, Order order); }
-    public interface ICustomUnitOrderGenerator : IOrderGenerator { };
     public interface INotifySold { void Selling(Actor self); void Sold(Actor self); }
     public interface INotifyDamage { void Damaged(Actor self, AttackInfo e); }
     public interface INotifyAppliedDamage { void AppliedDamage(Actor self, Actor damaged, AttackInfo e); }