LU-3339 mdt: HSM on disk actions record

LU-3339 mdt: HSM on disk actions record

HSM coordinator memorizes all actions in a llog
This patch implements the methods needed to create
update display these records.

Signed-off-by: JC Lafoucriere <jacques-charles.lafoucriere@cea.fr>
Change-Id: I58bdbbd52a75a841c30e4477f3cb4c942d6d2a20
Reviewed-on: http://review.whamcloud.com/6529
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>