LU-14810 lnet: Cancel discovery ping/push on shutdown

LU-14810 lnet: Cancel discovery ping/push on shutdown

Discovery shutdown can race with ping and push events. In some cases
this can result in failing to unlink ping/push MDs on shutdown.
Protect against this by checking for PING/PUSH_FAILED state on peers
on the request queue.

Lustre-change: https://review.whamcloud.com/53356
Lustre-commit: c3b9597742d5118a96f56129e7dd30d84468d2c8

Test-Parameters: trivial
Test-Parameters: testlist=sanity-lnet env=ONLY=500,ONLY_REPEAT=50
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I84a1f5beb6508651bc62e1dd93271f9e72f5081c
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/53848
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>