LU-15440 lnet: lnet_peer_data_present() memory leak

LU-15440 lnet: lnet_peer_data_present() memory leak

If the ping buffer has nnis <= 1 then the ref on the ping buffer does
not get dropped. This causes a memory leak.

Lustre-change: https://review.whamcloud.com/46052
Lustre-commit: 56384a4fc39ff99c8abb3538f93d303f2be6ab45

Test-Parameters: trivial testlist=sanity-lnet
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I5e3c651ffecbe4f8860afb86770cecef23ebe862
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/51684
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>