staging: lustre: avoid intensive reconnecting for ko2iblnd

staging: lustre: avoid intensive reconnecting for ko2iblnd

When there is a connection race between two nodes and one side
of the connection is rejected by the other side. o2iblnd will
reconnect immediately, this is going to generate a lot of
trashes if:

 - race winner is slow and can't send out connecting request
   in short time.
 - remote side leaves a cmid in TIMEWAIT state, which will reject
   future connection requests

To resolve this problem, this patch changed the reconnection
behave: reconnection is submitted by connd only if a zombie
connection is being destroyed and there is a pending
reconnection request for the corresponding peer.

Also, after a few rejections, reconnection will have a time
interval between each attempt.

Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7569
Reviewed-on: http://review.whamcloud.com/17892
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>