Index: wp-includes/nav-menu-template.php
===================================================================
--- wp-includes/nav-menu-template.php	(revision 26758)
+++ wp-includes/nav-menu-template.php	(working copy)
@@ -82,7 +82,7 @@
 	function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
 		$indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
 
-		$class_names = $value = '';
+		$class_names = '';
 
 		$classes = empty( $item->classes ) ? array() : (array) $item->classes;
 		$classes[] = 'menu-item-' . $item->ID;
@@ -111,7 +111,7 @@
 		$id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args );
 		$id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
 
-		$output .= $indent . '<li' . $id . $value . $class_names .'>';
+		$output .= $indent . '<li' . $id . $class_names .'>';
 
 		$atts = array();
 		$atts['title']  = ! empty( $item->attr_title ) ? $item->attr_title : '';