Description of problem:
Prometheus openshift-monitoring/kube-controller-manager target still uses 10252 after secure KCM is re-enabled.
In prometheus UI, saw "down":
http://10.0.138.175:10252/metrics
    down     endpoint="https" instance="10.0.138.175:10252" job="kube-controller-manager" namespace="openshift-kube-controller-manager" pod="kube-controller-manager-ip-10-0-138-175.ap-northeast-2.compute.internal" service="kube-controller-manager"     12.407s ago     1.468ms     Get http://10.0.138.175:10252/metrics: dial tcp 10.0.138.175:10252: connect: connection refused
http://10.0.142.164:10252/metrics
    down     endpoint="https" instance="10.0.142.164:10252" job="kube-controller-manager" namespace="openshift-kube-controller-manager" pod="kube-controller-manager-ip-10-0-142-164.ap-northeast-2.compute.internal" service="kube-controller-manager"     12.677s ago     1.299ms     Get http://10.0.142.164:10252/metrics: dial tcp 10.0.142.164:10252: connect: connection refused
http://10.0.148.220:10252/metrics
    down     endpoint="https" instance="10.0.148.220:10252" job="kube-controller-manager" namespace="openshift-kube-controller-manager" pod="kube-controller-manager-ip-10-0-148-220.ap-northeast-2.compute.internal" service="kube-controller-manager"     21.547s ago     506.6us     Get http://10.0.148.220:10252/metrics: dial tcp 10.0.148.220:10252: connect: connection refused

Version-Release number of selected component (if applicable):
4.0.0-0.nightly-2019-04-10-182914

How reproducible:
Always

Steps to Reproduce:
1. Visit prometheus UI, go to Targets page

Actual results:
1. Saw above "down": http://file.rdu.redhat.com/~xxia/kube-controller-manager.png

Expected results:
1. Should use https://...:10257/metrics

Additional info:
Secure 10257 is re-enabled per below result:
$ oc rsh -n openshift-kube-controller-manager kube-controller-manager-ip-10-0-138-175.ap-northeast-2.compute.internal
sh-4.2# curl -k https://10.0.138.175:10257/healthz 
ok
sh-4.2# curl http://10.0.138.175:10252/healthz
curl: (7) Failed connect to 10.0.138.175:10252; Connection refused