scratch.md: kubeconfig should not embed the CA cert

docs/getting-started-guides/scratch.md

@@ -280,7 +280,7 @@ users:
 clusters:
 - name: local
   cluster:
-    certificate-authority-data: ${CA_CERT_BASE64_ENCODED}
+    certificate-authority: /srv/kubernetes/ca.crt
 contexts:
 - context:
     cluster: local
@@ -289,10 +289,6 @@ contexts:
 current-context: service-account-context
 ```
 
-Where CA_CERT_BASE64_ENCODED can be generated like `< ca.crt base64
--w0`.  Alternatively you can refer to a file (e.g. `certificate-authority:
-/etc/kubernetes/ca.crt`).
-
 Put the kubeconfig(s) on every node.  The examples later in this
 guide assume that there are kubeconfigs in `/var/lib/kube-proxy/kubeconfig` and
 `/var/lib/kubelet/kubeconfig`.