eviter un NOTICE

git-svn-id: https://zone.spip.org/spip-zone/_core_/tests@43364 ac52e18a-acf5-0310-9fe8-c4428f23b10a

index.php

 <?php
-	$dir = $_GET['dir'] ? $_GET['dir'] : '..';
+	$dir = (isset($_GET['dir']) AND ($_GET['dir'])) ? $_GET['dir'] : '..';
 	chdir($dir);
 	require 'ecrire/inc_version.php';