修复bug

src/pages/system/account/index.vue

 <template>
   <div class="account">
-    <h5>账号管理 <el-button style="float:right;margin:12px 30px 0 0" size="mini"  type="primary" plain @click="handleAdd" v-if="!isSuperAdmin">添加账号</el-button></h5>
+    <h5>账号管理 <el-button style="float:right;margin:12px 30px 0 0" size="mini"  type="primary" plain @click="handleAdd" v-if="isSuperAdmin">添加账号</el-button></h5>
     <div class="inner">
       <el-table :data="listData" style="width: 100%" height="calc(100% - 32px)" v-loading="loading">
         <el-table-column prop="userid" label="ID" min-width="120"></el-table-column>