Remove signal handler registration from pkg/kubelet

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.

cmd/genkubedocs/gen_kube_docs.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/spf13/cobra/doc"
 	"github.com/spf13/pflag"
+	"k8s.io/apiserver/pkg/server"
 	ccmapp "k8s.io/kubernetes/cmd/cloud-controller-manager/app"
 	"k8s.io/kubernetes/cmd/genutils"
 	apiservapp "k8s.io/kubernetes/cmd/kube-apiserver/app"
@@ -53,7 +54,7 @@ func main() {
 	switch module {
 	case "kube-apiserver":
 		// generate docs for kube-apiserver
-		apiserver := apiservapp.NewAPIServerCommand()
+		apiserver := apiservapp.NewAPIServerCommand(server.SetupSignalHandler())
 		doc.GenMarkdownTree(apiserver, outDir)
 	case "kube-controller-manager":
 		// generate docs for kube-controller-manager
@@ -73,7 +74,7 @@ func main() {
 		doc.GenMarkdownTree(scheduler, outDir)
 	case "kubelet":
 		// generate docs for kubelet
-		kubelet := kubeletapp.NewKubeletCommand()
+		kubelet := kubeletapp.NewKubeletCommand(server.SetupSignalHandler())
 		doc.GenMarkdownTree(kubelet, outDir)
 	case "kubeadm":
 		// resets global flags created by kubelet or other commands e.g.