Push Ubuntu init script fixes upstream

[danielwhite]

In pull request #1, a custom init script was added to track the service status using a pid file. This was necessary because the service task would try to start the service, and it would simply start another icecast2 process.

It would be better if the upstream version was fixed more permanently, since the current version is rather badly behaved.

[danielwhite]

It's likely this isn't required, since we're entering the brave new world of systemd. Once we can run the tests on Docker containers with systemd, then the init script might be worth dropping altogether, and only focus on supporting later releases.