Improve security of sessions:

- use only cookies to store session id on client side
- use default php session system with database handler to store sessions on server side

git-svn-id: http://piwigo.org/svn/trunk@1004 68402e56-0260-453c-a942-63ccdbb3a9ee

random.php

@@ -59,5 +59,5 @@ while ($row = mysql_fetch_array($result))
 // |                                redirect                               |
 // +-----------------------------------------------------------------------+
 $url = PHPWG_ROOT_PATH.'category.php?cat=list&list='.implode(',', $ids);
-redirect(add_session_id($url));
+redirect($url);
 ?>