refactor($parse): make use of local variable instead of refetching property

Author: jbedard

src/ng/parse.js

@@ -1942,9 +1942,8 @@ function $ParseProvider() {
 
       // Propagate $$watchDelegates other then inputsWatchDelegate
       useInputs = !parsedExpression.inputs;
-      if (parsedExpression.$$watchDelegate &&
-          parsedExpression.$$watchDelegate !== inputsWatchDelegate) {
-        fn.$$watchDelegate = parsedExpression.$$watchDelegate;
+      if (watchDelegate && watchDelegate !== inputsWatchDelegate) {
+        fn.$$watchDelegate = watchDelegate;
         fn.inputs = parsedExpression.inputs;
       } else if (!interceptorFn.$stateful) {
         // If there is an interceptor, but no watchDelegate then treat the interceptor like