LU-11049 ssk: correctly handle null byte by lgss_sk

LU-11049 ssk: correctly handle null byte by lgss_sk

lgss_sk must include null byte with fsname and nodemap info taken from
command line.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: Ie98444c930b8df521482468c4897e080ded0d2f6
Reviewed-on: https://review.whamcloud.com/32510
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Jeremy Filizetti <jeremy.filizetti@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>