Fatal error when reordering book pages in book admin

Thanks for the quick patch larowlan! One thing that I noticed:

+++ b/core/modules/book/book.admin.inc
@@ -150,6 +150,8 @@ function book_admin_edit_submit($form, &$form_state) {
     if ($form['table'][$key]['#item']) {
       $row = $form['table'][$key];
@@ -159,7 +161,11 @@ function book_admin_edit_submit($form, &$form_state) {

@@ -159,7 +161,11 @@ function book_admin_edit_submit($form, &$form_state) {
       if ($row['plid']['#default_value'] != $values['plid'] || $row['weight']['#default_value'] != $values['weight']) {
         $row['#item']['plid'] = $values['plid'];
         $row['#item']['weight'] = $values['weight'];
-        menu_link_save($row['#item']);
+        $menu_link = entity_load('menu_link', $values['mlid']);
+        $menu_link->weight = $values['weight'];
+        $menu_link->plid = $values['plid'];
+        $menu_link->save();
+        $updated = TRUE;

Since #item is no longer used, should it be removed? At the very least, the assignments to $row['#item']['plid'] and $row['#item']['weight'] should be removed.

Also, the tests should probably be updated to include testing for changing book parents, not just weight.