Don’t create old or new values in KVO change dictionary when doing bindings

AppKit/CPKeyValueBinding.j

@@ -156,7 +156,7 @@ var CPBindingOperationAnd = 0,
 
         [self _updatePlaceholdersWithOptions:options forBinding:aName];
 
-        [aDestination addObserver:self forKeyPath:aKeyPath options:CPKeyValueObservingOptionNew context:aBinding];
+        [aDestination addObserver:self forKeyPath:aKeyPath options:0 context:aBinding];
 
         var bindings = [bindingsMap objectForKey:[_source UID]];