Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Use kubernetes image repo for coredns
Fixes#927
Signed-off-by: Chuck Ha <ha.chuck@gmail.com>
**What this PR does / why we need it**:
use the coredns image from the k8s image repository when building a cluster with kubeadm
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixeskubernetes/kubeadm#927
```release-note
NONE
```
/cc @kubernetes/sig-cluster-lifecycle-pr-reviews
/assign @luxas