staging/lustre/osc: Remove commented out osc_page_protected()

The complicated version of osc_page_protected and osc_page_is_dlocked
are unsafe and were commented out for ages, so probably no point in
carrying them on.

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