nvme-rdma: reject non-connect commands before the queue is live

If we reconncect we might have command queue up that get resent as soon
as the queue is restarted.  But until the connect command succeeded we
can't send other command.  Add a new flag that marks a queue as live when
connect finishes, and delay any non-connect command until the queue is
live based on it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Steve Wise <swise@opengridcomputing.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
[sagig: fixes admin queue LIVE setting]
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>