fixed missing column heading

management/templates/users.html

@@ -47,7 +47,6 @@
   <thead>
     <tr>
       <th width="35%">Email Address</th>
-      <th class="row-center">Messages</th>
       <th class="row-center">Size</th>
       <th class="row-center">Used</th>
       <th class="row-center">Quota</th>