InvertedShellWrapper may not send process output back if process exits too fast

In InvertedShellWrapper, pumpStreams() method first checks if the process is alive, and only then pumps streams. It could happen that after the process has already exited, some information is left out in out or err streams. Moving the check for shell.isAlive() after all pumpStream() calls seems to resolve the issue.

I've uploaded a patch for your convenience here https://gist.github.com/1206056

steps to reproduce:

1. create a default server
2. set command factory as described at http://mina.apache.org/sshd/tips.html
3. run `ssh localhost -p 8000 echo test`

expected result:
command output is `test`

actual result:
usually nothing is printed even though the command is executed