In menu_link_save, the comparison between existing item and current item does not check all data.

I ran into this issue when trying to use the deploy module with an entity menu item that had been given fields. During the comparison with `(array_intersect_key($item, $existing_item) != $existing_item)`, it does not take fields into consideration and will assume the menu item is the same and won't save (and also won't trigger menu_link_insert or menu_link_update).

My fix was to add a property on the menu item for "force_save" and use hook_menu_link_alter to toggle it to TRUE.