Fix kubelet_kubelet_cgroups_cgroupfs (kubernetes-sigs#8500)

If kubelet is run with systemd (as it always is when using kubespray),
it starts in systemd's /system.slice/kubelet.service cgroup.

This commit prevents a creation and usage of a second unrelated cgroup.

roles/kubernetes/node/defaults/main.yml

@@ -30,7 +30,7 @@ kubelet_kubelet_cgroups: "/systemd/system.slice"
 
 # Set runtime and kubelet cgroups when using cgroupfs as cgroup driver
 kubelet_runtime_cgroups_cgroupfs: "/system.slice/containerd.service"
-kubelet_kubelet_cgroups_cgroupfs: "/system.slice/kubelet.slice"
+kubelet_kubelet_cgroups_cgroupfs: "/system.slice/kubelet.service"
 
 ### fail with swap on (default true)
 kubelet_fail_swap_on: true