Fix duplicate --proxy-client-cert-file and --proxy-client-key-file

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

@@ -57,8 +57,6 @@ spec:
 {% endif %}
     - --tls-cert-file={{ kube_cert_dir }}/apiserver.pem
     - --tls-private-key-file={{ kube_cert_dir }}/apiserver-key.pem
-    - --proxy-client-cert-file={{ kube_cert_dir }}/apiserver.pem
-    - --proxy-client-key-file={{ kube_cert_dir }}/apiserver-key.pem
 {% if kube_token_auth|default(true) %}
     - --token-auth-file={{ kube_token_dir }}/known_tokens.csv
 {% endif %}