staging/lustre: Remove server-only recovery-related bits

This patch is a first stab at trying to remove structure fields
from obd_export and obd structures that are only used on the
server or make sense on the server. These include tracking
requests in recovery, various recovery stages, lists of
recovered and not yet recovered clients and so on.
Also prune functions that use these fields.

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