staging/lustre: Replace jobid acquiring with per node setting

Insted of meddling directly in process environment variables
(which is also not possible on certain platforms due to not exported
symbols), create jobid_name proc file to represent this info
(to be filled by job scheduler epilogue).

Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
CC: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>