block/rnbd-clt: send_msg_close if any error occurs after send_msg_open

After send_msg_open is done, send_msg_close should be done
if any error occurs and it is necessary to recover
what has been done.

Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>