Stop templating kube-system namespace and creating it (#2545)

Kubernetes makes this namespace automatically, so there is
no need for kubespray to manage it.

roles/kubernetes-apps/ansible/templates/kubedns-autoscaler.yml.j2

@@ -17,7 +17,7 @@ apiVersion: extensions/v1beta1
 kind: Deployment
 metadata:
   name: kubedns-autoscaler
-  namespace: {{ system_namespace }}
+  namespace: kube-system
   labels:
     k8s-app: kubedns-autoscaler
     kubernetes.io/cluster-service: "true"
@@ -40,7 +40,7 @@ spec:
             memory: "10Mi"
         command:
         - /cluster-proportional-autoscaler
-        - --namespace={{ system_namespace }}
+        - --namespace=kube-system
         - --configmap=kubedns-autoscaler
         # Should keep target in sync with cluster/addons/dns/kubedns-controller.yaml.base
         - --target=Deployment/kube-dns