rport forwarding - unstable

hi,

while using sshj against openssh with rport forwarding enabled

``` java
sshClient.getRemotePortForwarder().bind(new Forward(p), new SocketForwardingConnectListener(new InetSocketAddress("localhost", localPort)));
```

i am getting a lot of disconnects (after some minutes, but never got it to an hour)

server log:

```
Jan 12 14:37:43 catbox sshd[11984]: channel_by_id: 4: bad id: channel free
Jan 12 14:37:43 catbox sshd[11984]: Disconnecting: Received data for nonexistent channel 4.
```

client log:

```
2012-01-12 14:37:11,235 ERROR [net.schmizz.sshj.transport.TransportImpl] Dying because - net.schmizz.sshj.transport.TransportException: [PROTOCOL_ERROR] Disconnected; server said: Received data for nonexistent channel 4.
2012-01-12 14:37:20,785 ERROR [net.schmizz.sshj.common.StreamCopier] In pipe from java.net.SocketInputStream@4434d2ab to < ChannelOutputStream for Channel #0 >: net.schmizz.sshj.transport.TransportException: Broken pipe
2012-01-12 14:37:20,785 ERROR [net.schmizz.sshj.transport.TransportImpl] Dying because - net.schmizz.sshj.transport.TransportException: Broken pipe
2012-01-12 14:37:20,786 ERROR [net.schmizz.concurrent.Promise] <> woke to: net.schmizz.sshj.transport.TransportException: Broken pipe
```

_note:_ log timestamps don't fit because one hosts clock is off some seconds
_edit:_ changed title to reflect severity