Index: wp-admin/admin-ajax.php
===================================================================
--- wp-admin/admin-ajax.php	(revision 15270)
+++ wp-admin/admin-ajax.php	(working copy)
@@ -956,7 +956,6 @@
 	define( 'DOING_AUTOSAVE', true );
 
 	$nonce_age = check_ajax_referer( 'autosave', 'autosavenonce' );
-	global $current_user;
 
 	$_POST['post_category'] = explode(",", $_POST['catslist']);
 	if ( $_POST['post_type'] == 'page' || empty($_POST['post_category']) )