The goal of this change is to remove the registration of signal
handling from pkg/kubelet. We now pass in a stop channel.
If you register a signal handler in `main()` to aid in a controlled
and deliberate exit then the handler registered in `pkg/kubelet` often
wins and the process exits immediately. This means all other signal
handler registrations are currently racy if `DockerServer.Start()` is
directly or indirectly invoked.
This change also removes another signal handler registration from
`NewAPIServerCommand()`; a stop channel is now passed to this
function.
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