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/calico/templates/calico-config.yml.j2

@@ -2,7 +2,7 @@ kind: ConfigMap
 apiVersion: v1
 metadata:
   name: calico-config
-  namespace: {{ system_namespace }}
+  namespace: kube-system
 data:
   etcd_endpoints: "{{ etcd_access_addresses }}"
   etcd_ca: "/calico-secrets/ca_cert.crt"