LU-6501 libcfs: removal last entry of libcfs_netstrfns[]

LU-6501 libcfs: removal last entry of libcfs_netstrfns[]

Currently NID string handling test for the last entry,
and last entry has .nf_type == (__u32) -1. If we ask
for a non existent LND we hit the last entry which then
calls a strlen on a NULL which causes a error. We can
avoid this problem if we just remove the last entry
since it is not used for anything except as a last
entry marker.

Signed-off-by: Frederic Saunier <frederic.saunier@atos.net>
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Change-Id: Ia8e3bea0f01bb5fa78e88bfbca698b0aa0d148ea
Reviewed-on: http://review.whamcloud.com/15424
Tested-by: Jenkins
Reviewed-by: frank zago <fzago@cray.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>