No need for authentication on url.php (bug#3168011).

url.php

@@ -3,14 +3,14 @@
  * URL redirector to avoid leaking Referer with some sensitive information.
  */
 
+define('PMA_MINIMUM_COMMON', TRUE);
+
 /**
  * Gets core libraries and defines some variables
  */
 require_once './libraries/common.inc.php';
 
-PMA_checkParameters(array('url'));
-
-if (! preg_match('/^https?:\/\/[^\n\r]*$/', $GLOBALS['url'])) {
+if (empty($GLOBALS['url']) || ! preg_match('/^https?:\/\/[^\n\r]*$/', $GLOBALS['url'])) {
     header('Location: ' . $cfg['PmaAbsoluteUri']);
 } else {
     header('Location: ' . $GLOBALS['url']);