staging/lustre: Remove mds/ost capabilities support

Client capabilities is an outdated feature that never worked properly,
so let's get rid of the client support since modern servers
don't have this support either.

The patch is big, but since it just removes one large feature,
so it's hopefully easy to verify.

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