Enable quorum read for apiserver

This reduces the likelihood of apiserver status updates
timing out due to etcd write conflicts.

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

@@ -13,6 +13,7 @@ spec:
     - apiserver
     - --advertise-address={{ ip | default(ansible_default_ipv4.address) }}
     - --etcd-servers={{ etcd_access_endpoint }}
+    - --etcd-quorum-read=true
     - --insecure-bind-address={{ kube_apiserver_insecure_bind_address }}
     - --apiserver-count={{ kube_apiserver_count }}
     - --admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,ServiceAccount,ResourceQuota