Namespace the UserController

refs #5786

application/controllers/UserController.php

@@ -1,6 +1,8 @@
 <?php
 /* Icinga Web 2 | (c) 2013-2015 Icinga Development Team | GPLv2+ */
 
+namespace Icinga\Controllers;
+
 use Icinga\Application\Logger;
 use Icinga\Data\DataArray\ArrayDatasource;
 use Icinga\Exception\ConfigurationError;