Merge pull request #1018 from iview/2.0

如果没有开启多语言，不显示切换语言下拉菜单

Author: Lison

src/components/main/main.vue

@@ -13,7 +13,7 @@
       <Header class="header-con">
         <header-bar :collapsed="collapsed" @on-coll-change="handleCollapsedChange">
           <user :user-avator="userAvator"/>
-          <language @on-lang-change="setLocal" style="margin-right: 10px;" :lang="local"/>
+          <language v-if="$config.useI18n" @on-lang-change="setLocal" style="margin-right: 10px;" :lang="local"/>
           <fullscreen v-model="isFullscreen" style="margin-right: 10px;"/>
         </header-bar>
       </Header>