LU-18899 o2iblnd: handle RDMA_CM_EVENT_ESTABLISHED gracefully

LU-18899 o2iblnd: handle RDMA_CM_EVENT_ESTABLISHED gracefully

Modify kiblnd_cm_callback() to handle RDMA_CM_EVENT_ESTABLISHED
gracefully: report an error with relevant details and ignore
the event rather than just cause a crash with LBUG
if the connection state is not RDMA_CM_EVENT_ESTABLISHED or
IBLND_CONN_PASSIVE_WAIT as expected.

Test-Parameters: trivial testlist=sanity-lnet
Signed-off-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Change-Id: I8ddde6786eac99699665a71eb0587165e6552ea6
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58711
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>
Reviewed-by: Oleg Drokin <green@whamcloud.com>