LU-13779 lnet: Correct asymmetric route detection

LU-13779 lnet: Correct asymmetric route detection

Failure to lookup the remote net for LNET_NIDNET(src_nid) indicates an
asymmetric route, but we do not drop the message in this case. Another
problem with this code is that there is no guarantee that we'll have a
route->lr_lnet that matches the net of ni->ni_nid.

We can move the asymmetric route detection to after we have looked up
the lpni of from_nid. Then, we can look at just the routes associated
with the gateway that owns the lpni. If one of those routes has
lr_net == LNET_NIDNET(src_nid), then the route is symmetrical.

Lustre-change: https://review.whamcloud.com/39349
Lustre-commit: 955080c3ae3f33c98e068f52a096761ea28624b7

Fixes: 4932febc12 ("LU-11894 lnet: check for asymmetrical route messages")
Test-Parameters: trivial
HPE-bug-id: LUS-9087
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I8044d3f53e6f000c1e4d7c4e34b3b21afe0f9711
Reviewed-on: https://review.whamcloud.com/48334
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>