LU-9667 lnet: Error out on missing network device information

LU-9667 lnet: Error out on missing network device information

Per the sysfs design, a network interface is always needed
to create the sysfs hierarchy for LNet NI while adding a
new NI.

To accomodate this, error out if the network interface
is not specified.

Change-Id: Ic128c2fa3509864bb06ee3bec490d41559c1a0c3
Test-Parameters: trivial
Signed-off-by: Sonia Sharma <sharmaso@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/33583
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>