Fix redux integration for react-navigation 2.

index.js

@@ -1,7 +1,6 @@
 "use strict";
 
 import React, {Component} from 'react';
-import {addNavigationHelpers} from 'react-navigation';
 import {createReactNavigationReduxMiddleware, createReduxBoundAddListener} from 'react-navigation-redux-helpers';
 import {connect} from 'react-redux';
 
@@ -14,7 +13,7 @@ export const navigatorPieces = (BareNavigator, name = "root") => {
         render () {
             const {dispatch, navigationState} = this.props;
             return <BareNavigator
-                navigation={addNavigationHelpers({dispatch, state: navigationState, addListener})}
+                navigation={{dispatch, state: navigationState, addListener}}
             />;
         }
     }