fix ListView to work with Native Animated.event

Summary:
suggested by janicduplessis in https://github.com/facebook/react-native/pull/9253#issuecomment-247862707
I'm using this in my own apps
Closes https://github.com/facebook/react-native/pull/11339

Differential Revision: D4325343

fbshipit-source-id: f1da26a2107093865f04e1d81245b33482776001

Libraries/CustomComponents/ListView/ListView.js

@@ -268,6 +268,14 @@ var ListView = React.createClass({
     }
   },
 
+  getScrollableNode: function() {
+    if (this._scrollComponent && this._scrollComponent.getScrollableNode) {
+      return this._scrollComponent.getScrollableNode();
+    } else {
+      return ReactNative.findNodeHandle(this._scrollComponent);
+    }
+  },
+
   /**
    * Scrolls to a given x, y offset, either immediately or with a smooth animation.
    *