LU-9578 llite: use security context if it's enabled in the kernel

LU-9578 llite: use security context if it's enabled in the kernel

if it's disabled, then Lustre stop to work properly (can not create
files, etc)

Change-Id: I1e431ec95a2b0613b43893567eb6d1a64ec832de
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: https://review.whamcloud.com/27364
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Reviewed-by: Chris Horn <hornc@cray.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>