LU-7943 mdd: Move assignment after LASSERT()

LU-7943 mdd: Move assignment after LASSERT()

This patch moves 'sname->ln_namelen' assignment call after LASSERT() call.
This avoids a case when 'sname' parameter is NULL and dereferencing the
NULL pointer would fault before it reaches LASSERT()

Change-Id: I68b07f7ca33fd21ee0599b7bb73d6e41546bd2d8
Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Reviewed-on: https://review.whamcloud.com/32376
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>