LU-17000 lnet: Initilize lnet_nidlist local variable

LU-17000 lnet: Initilize lnet_nidlist local variable

Initialize vairbale lnet_nidlist under
lustre_lnet_modify_peer(). This is due to a case
where "nids" is false lustre_lnet_mod_peer_nidlist()
is called with lnet_nidlist uninitialized.

Test-Parameters: trivial testlist=sanity-lnet
CoverityID 397609: ("Uninitialized scalar variable")
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I07de6a637c4567daed4ce7b35c54a1eed4d9bd2f
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55290
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>