Attempt reduxjs#6: applyMiddleware Code

const dispatch = store.dispatch;
needs to be changed to:
let dispatch = store.dispatch;
because dispatch will updated later in the code

Author: BBBeta

docs/advanced/Middleware.md

@@ -253,7 +253,7 @@ Instead of `applyMiddlewareByMonkeypatching()`, we could write `applyMiddleware(
 function applyMiddleware(store, middlewares) {
   middlewares = middlewares.slice()
   middlewares.reverse()
-  const dispatch = store.dispatch
+  let dispatch = store.dispatch
   middlewares.forEach(middleware =>
     dispatch = middleware(store)(dispatch)
   )