GUACAMOLE-220: Add semantic CSS class for headers having corresponding tabs.

guacamole/src/main/webapp/app/manage/templates/manageUser.html

@@ -2,7 +2,7 @@
 <div class="manage-user view" ng-class="{loading: !isLoaded()}">
 
     <!-- User header and data source tabs -->
-    <div class="username header">
+    <div class="header tabbed">
         <h2>{{'MANAGE_USER.SECTION_HEADER_EDIT_USER' | translate}}</h2>
         <guac-user-menu></guac-user-menu>
     </div>