LU-17000 lnet: don't assign unused return codes

LU-17000 lnet: don't assign unused return codes

In lnet_peer_discovery() return from lnet_peer_ping_failed()
and lnet_peer_push_failed() is unused and return value of
former get quashed without getting used.

Remove rc assignment and cast function to void to make it
clear the return code can be ignored.

Test-Parameters: trivial
CoverityID: 412758 ("Unused Value")
CoverityID: 412759 ("Unused Value")
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I02d5e883fc02814d5dbe307b78f028703023db52
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/53608
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>