Don't referece not-exist addon manager manifests in comment

cluster/saltbase/salt/kube-addons/kube-addon-manager.yaml

@@ -12,8 +12,6 @@ spec:
   containers:
   - name: kube-addon-manager
     # When updating version also bump it in:
-    # - cluster/images/hyperkube/static-pods/addon-manager-singlenode.json
-    # - cluster/images/hyperkube/static-pods/addon-manager-multinode.json
     # - test/kubemark/resources/manifests/kube-addon-manager.yaml
     image: gcr.io/google-containers/kube-addon-manager:v6.4-beta.2
     command: