fix dist build export

Author: yyx990803

examples/todomvc/vuex/middlewares.js

@@ -1,5 +1,5 @@
 import { STORAGE_KEY } from './store'
-import { createLogger } from '../../../src'
+import Vuex from '../../../src'
 
 const localStorageMiddleware = {
   onMutation (mutation, { todos }) {
@@ -8,5 +8,5 @@ const localStorageMiddleware = {
 }
 
 export default process.env.NODE_ENV !== 'production'
-  ? [createLogger(), localStorageMiddleware]
+  ? [Vuex.createLogger(), localStorageMiddleware]
   : [localStorageMiddleware]

src/index.js

@@ -5,7 +5,7 @@ import override from './override'
 
 let Vue
 
-export class Store {
+class Store {
 
   /**
    * @param {Object} options
@@ -245,12 +245,6 @@ function install (_Vue) {
   override(Vue)
 }
 
-export {
-  install,
-  createLogger
-}
-
-// also export the default
 export default {
   Store,
   install,