kubelet: Add --exit-on-lock-contention flag

This patch adds the --exit-on-lock-contention flag, which must be used
in conjunction with the --lock-file flag. When provided, it causes the
kubelet to wait for inotify events for that lock file. When an 'open'
event is received, the kubelet will exit.

pkg/kubelet/container/runtime.go

@@ -69,7 +69,7 @@ type Runtime interface {
 	APIVersion() (Version, error)
 	// Status returns error if the runtime is unhealthy; nil otherwise.
 	Status() error
-	// GetPods returns a list containers group by pods. The boolean parameter
+	// GetPods returns a list of containers grouped by pods. The boolean parameter
 	// specifies whether the runtime returns all containers including those already
 	// exited and dead containers (used for garbage collection).
 	GetPods(all bool) ([]*Pod, error)