LU-4629 utils: fix NULL pointer dereference

LU-4629 utils: fix NULL pointer dereference

'uuid' and 'lnet' can be NULL. So check for this case.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Change-Id: I06ead7470649054ca5bd0e0395f5e817c08bc2db
Reviewed-on: http://review.whamcloud.com/10136
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>