avoid error Call to a member function getThemeUniqueValue() on a non-object

libraries/auth/cookie.auth.lib.php

@@ -397,7 +397,9 @@ function PMA_auth_check()
         // -> delete his choices that were stored in session
 
         // according to the PHP manual we should do this before the destroy:
-        $_SESSION = array();
+        //$_SESSION = array();
+        // but we still need some parts of the session information
+        // in libraries/header_meta_style.inc.php
 
         session_destroy();
         // -> delete password cookie(s)