LU-15618 lnet: Return ESHUTDOWN in lnet_parse()

LU-15618 lnet: Return ESHUTDOWN in lnet_parse()

If the peer NI lookup in lnet_parse() fails with ESHUTDOWN then we
should return that value back to the LNDs so that they can treat the
failed call the same way as other lnet_parse() failures.

Returning zero results in at least one bug in socklnd where a
reference on a ksock_conn can be leaked which prevents socklnd from
shutting down.

Lustre-change: https://review.whamcloud.com/46711
Lustre-commit: 4fbd0705a3d25bbc85e953f81e697e5006b215ce

Fixes: 47b7b31978 ("LU-8106 lnet: Do not drop message when shutting down LNet")
Test-Parameters: trivial testlist=sanity-lnet
HPE-bug-id: LUS-15794
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: Ic403619c6dccf3921c46a674808c404adad7a30e
Reviewed-on: https://review.whamcloud.com/48485
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>