Description of problem:
When installing containerized ha-master 3.9 cluster, prerequisites.yml playbook didn't configure necessary docker registry params on the lb host, then the installation failed for it couldn't pull haproxy image.


Version-Release number of the following components:
$ git describe
openshift-ansible-3.9.0-0.10.0-54-g7d2dee3
ansible-2.4.2.0-1.el7ae.noarch

How reproducible:
Always

Steps to Reproduce:
1. Prepare ansible inventory file, run the following playbooks 

#ansible-playbook -v openshift-ansible/playbooks/prerequisites.yml
#ansible-playbook -v openshift-ansible/playbooks/deploy_cluster.yml


Actual results:
TASK [openshift_loadbalancer : Install haproxy] ********************************
Friday 22 December 2017  03:47:45 +0000 (0:00:00.021)       0:04:26.157 ******* 
skipping: [ec2-54-236-77-189.compute-1.amazonaws.com] => {"changed": false, "skip_reason": "Conditional result was False"}

TASK [openshift_loadbalancer : Pull haproxy image] *****************************
Friday 22 December 2017  03:47:45 +0000 (0:00:00.026)       0:04:26.183 ******* 
fatal: [ec2-54-236-77-189.compute-1.amazonaws.com]: FAILED! => {"changed": true, "cmd": ["docker", "pull", "openshift3/ose-haproxy-router:v3.9.0-0.9.0"], "delta": "0:00:01.350727", "end": "2017-12-22 03:47:47.275027", "msg": "non-zero return code", "rc": 1, "start": "2017-12-22 03:47:45.924300", "stderr": "Error: image openshift3/ose-haproxy-router:v3.9.0-0.9.0 not found", "stderr_lines": ["Error: image openshift3/ose-haproxy-router:v3.9.0-0.9.0 not found"], "stdout": "Trying to pull repository registry.access.redhat.com/openshift3/ose-haproxy-router ... \nTrying to pull repository docker.io/openshift3/ose-haproxy-router ... \nPulling repository docker.io/openshift3/ose-haproxy-router", "stdout_lines": ["Trying to pull repository registry.access.redhat.com/openshift3/ose-haproxy-router ... ", "Trying to pull repository docker.io/openshift3/ose-haproxy-router ... ", "Pulling repository docker.io/openshift3/ose-haproxy-router"]}
        to retry, use: --limit @/home/slave5/workspace/Launch-Environment-Flexy/private-openshift-ansible/playbooks/deploy_cluster.retry



On lb host:
-bash-4.2# cat /etc/sysconfig/docker
# /etc/sysconfig/docker

# Modify these options if you want to change the way the docker daemon runs
OPTIONS='--selinux-enabled --log-driver=journald --signature-verification=false'
if [ -z "${DOCKER_CERT_PATH}" ]; then
    DOCKER_CERT_PATH=/etc/docker
fi

# Do not add registries in this file anymore. Use /etc/containers/registries.conf
# from the atomic-registries package.
#

# docker-latest daemon can be used by starting the docker-latest unitfile.
# To use docker-latest client, uncomment below lines
#DOCKERBINARY=/usr/bin/docker-latest
#DOCKERDBINARY=/usr/bin/dockerd-latest
#DOCKER_CONTAINERD_BINARY=/usr/bin/docker-containerd-latest
#DOCKER_CONTAINERD_SHIM_BINARY=/usr/bin/docker-containerd-shim-latest
-bash-4.2# 


Expected results:
Installer should configure registry params in /etc/sysconfig/docker first

Additional info: