Add logging to the popit-daemon-debian init script

This will hopefully give a bit more of an insight into why the process
sometimes restarts. The solution was adapted from this SO answer [1].

[1] http://stackoverflow.com/a/12662904
Always send logs to stdout/stderr

Rather than trying to log to a file from within node, just send the logs
to the console and let the init script handle where they are sent after
that.