staging/lustre: Remove commented out obd functions

obd_register_page_removal_cb, obd_unregister_page_removal_cb
obd_register_lock_cancel_cb, obd_unregister_lock_cancel_cb

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>