hotfix bootstrap 3 bug

sails/src/assets/scripts/modules/supervisor/views/students.html

@@ -19,7 +19,7 @@
         </div>
         </div>
         <div class="col-xs-6 input-group">
         <div class="col-xs-6 input-group">
           <input type="text" ng-model="search_students" id="search_students" placeholder="{{ 'filter' | translate }}" class="form-control" aria-describedby="basic-addon2">
           <input type="text" ng-model="search_students" id="search_students" placeholder="{{ 'filter' | translate }}" class="form-control" aria-describedby="basic-addon2">
-          <span class="input-group-addon glyphicon glyphicon-search" id="basic-addon2" aria-hidden="true"></span>
+          <span class="input-group-addon"><span class="glyphicon glyphicon-search" id="basic-addon2" aria-hidden="true"></span></span>
         </div>
         </div>
         <div class="col-xs-3">
         <div class="col-xs-3">
       </div>
       </div>