add manual test for removal

Author: dashpole

keps/sig-node/2129-remove-cadvisor-json-metrics/README.md

@@ -29,11 +29,11 @@
 ## Release Signoff Checklist
 
 - [X] (R) Enhancement issue in release milestone, which links to KEP dir in [kubernetes/enhancements](https://github.com/kubernetes/enhancements/issues/1867)
-- [ ] (R) KEP approvers have approved the KEP status as `implementable`
+- [X] (R) KEP approvers have approved the KEP status as `implementable`
 - [X] (R) Design details are appropriately documented
-- [ ] (R) Test plan is in place, giving consideration to SIG Architecture and SIG Testing input
+- [X] (R) Test plan is in place, giving consideration to SIG Architecture and SIG Testing input
 - [X] (R) Graduation criteria is in place
-- [ ] (R) Production readiness review completed
+- [X] (R) Production readiness review completed
 - [ ] Production readiness review approved
 - [ ] "Implementation History" section is up-to-date for milestone
 - [ ] User-facing documentation has been created in [kubernetes/website], for publication to [kubernetes.io]
@@ -102,6 +102,7 @@ Remove the `--enable-cadvisor-json-endpoints` flag and the kubelet stops serving
 
 * This will not have any e2e testing.
 * There are no existing kubernetes e2e tests which check these endpoints.
+* When removing the endpoints, we will manually test that the endpoints are no longer being served.
 
 ### Graduation Criteria