Add int. tests for pidfile creation/removal
Wait indef. for a controlled shutdown for RedHat distros

Thought it would be a lot nicer to actually wait for Kafka to shutdown
when `controlled.shutdown.enable` is set to `true`, so that one can use
the `restart` action.

Unfortunately I had to write a simplified version of `killproc` to
actually get this to work. I hate init scripts.
Wait indef. for a controlled shutdown on Debian

If I understand the documentation for `start-stop-daemon`, giving a
`—signal` parameter it won’t force-kill a process.