staging/lustre/mdt: HSM coordinator client interface

This patch implements the HSM coordinator methods
used by client to add/remove/list HSM actions on
FID.

Lustre-change: http://review.whamcloud.com/6532
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3341
Signed-off-by: JC Lafoucriere <jacques-charles.lafoucriere@cea.fr>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>