LU-16011 lnet: remove LBUG() in srpc_client_rpc_expired()

LU-16011 lnet: remove LBUG() in srpc_client_rpc_expired()

We shouldn't crash just because an RPC expired.

Fixes: e5026380 ("LU-16011 lnet: use preallocate bulk for server")
Test-Parameters: trivial
Test-Parameters: testgroup=review-ldiskfs-arm testlist=sanity-lnet,lnet-selftest
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: Ia4e9bf7f688b2920c91444f57f7a7da2b1f89a67
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55785
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>