Adding in certificate serial numbers to manifests (#1392)

roles/kubernetes/master/templates/manifests/kube-scheduler.manifest.j2

@@ -5,6 +5,8 @@ metadata:
   namespace: {{ system_namespace }}
   labels:
     k8s-app: kube-scheduler
+  annotations:
+    kubespray.scheduler-cert/serial: "{{ scheduler_cert_serial }}"
 spec:
   hostNetwork: true
 {% if kube_version | version_compare('v1.6', '>=') %}