Description of problem:

After recent limits changes, we would like to configure cluster-wide credentials for pulling images from docker.io

Adding the docker.io credentials to /var/lib/origin as mentioned in the DOC[0], still running the pod fails with the below error:

`Failed to pull image "docker.io/XXXX/lgtestrepo:latest": rpc error: code = Unknown desc = repository docker.io/XXXX/lgtestrepo not found: does not exist or no pull access`

Followed [1][2], no luck

[0] https://docs.openshift.com/container-platform/3.11/install_config/configuring_red_hat_registry.html#using-service-accounts_configuring_red_hat_registry

[1] https://access.redhat.com/solutions/4661641
[2] https://access.redhat.com/RegistryAuthentication#red-hat-registries-1

Version-Release number of selected component (if applicable):
3.11.487

How reproducible:

Steps to Reproduce:
1. Create an account on docker.io and create a private repo with some image in it.
2. Login to docker from any of the worker node and
copy the .docker/config to /var/lib/origin/.docker/config.json and `systemctl restart atomic-openshift-node`

3. Logout and try to schedule a pod on the above node with the respective docker.io repo image

Actual results:
Fails to authenticate, pull the image and run the pod.

Expected results:
Should be able to authenticate, pull the image and run pod

Additional info:

Also fails with the same error if we define imagePullSecrets in the pod[3]

[3] https://docs.openshift.com/container-platform/3.11/dev_guide/managing_images.html#using-image-pull-secrets