staging: lustre: hsm: make HSM modification requests replayable

There are several HSM requests which modify data on server and
reply on Lustre recovery, e.g. they should replay changes in
case of recovery.

Patch allows such requests to be replayed in recovery time and
they are issued from client using mdc_rpc_lock to serialize them
and avoid concurrent last_rcvd update on server.

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5939
Reviewed-on: http://review.whamcloud.com/13684


Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>