LU-10554 lnet: Remove LASSERT on userspace data

If the net information is not provided while adding
NI, it results in an LBUG. Remove the LASSERT on
userspace input and handle it gracefully.

Test-Parameters: trivial
Change-Id: I9d2b6f94cb35e94bc81d5c52936d32cbf833e597
Signed-off-by: Sonia Sharma <sonia.sharma@intel.com>
Reviewed-on: https://review.whamcloud.com/31100


Tested-by: Jenkins
Reviewed-by: Amir Shehata <amir.shehata@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>