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/network_plugin/contiv/templates/contiv-etcd-proxy.yml.j2

@@ -3,7 +3,7 @@ kind: DaemonSet
 apiVersion: extensions/v1beta1
 metadata:
   name: contiv-etcd-proxy
-  namespace: {{ system_namespace }}
+  namespace: kube-system
   labels:
     k8s-app: contiv-etcd-proxy
 spec: