Description of problem:
Openshift installer trying to install docker on dedicated etcd hosts.

Version-Release number of selected component (if applicable):
3.1.1.6

How reproducible:
100%

Steps to Reproduce:
1. Add "--exclued=docker*" to etcd hosts /etc/yum.conf file
2. Run ansible-playbook /usr/share/ansible/openshift-ansible/playbooks/byo/config.ym


Actual results:
Failed due to trying to install docker

Expected results:
Skip installing docker on dedicated etcd host unless containerized. 


Additional info:

[root@ose ~]# rpm -qa | grep openshift
atomic-openshift-3.1.1.6-4.git.32.adf8ec9.el7aos.x86_64
openshift-ansible-filter-plugins-3.0.47-1.git.0.4498ce3.el7aos.noarch
openshift-ansible-lookup-plugins-3.0.47-1.git.0.4498ce3.el7aos.noarch
atomic-openshift-utils-3.0.47-1.git.0.4498ce3.el7aos.noarch
openshift-ansible-3.0.47-1.git.0.4498ce3.el7aos.noarch
openshift-ansible-playbooks-3.0.47-1.git.0.4498ce3.el7aos.noarch
atomic-openshift-clients-3.1.1.6-4.git.32.adf8ec9.el7aos.x86_64
openshift-ansible-roles-3.0.47-1.git.0.4498ce3.el7aos.noarch

----------------------------

[root@ose ~]# cat /etc/ansible/hosts
#Create an OSEv3 group that contains the masters and nodes groups
[OSEv3:children]
masters
nodes
etcd 

#Set variables common for all OSEv3 hosts
[OSEv3:vars]
deployment_type=openshift-enterprise
openshift_master_identity_providers=[{'name': 'allowall', 'login': 'true', 'challenge': 'true', 'kind': 'HTPasswdPasswordIdentityProvider', 'filename': '/etc/openshift/htpasswd'}]
sm_cluster_network_cidr=10.4.0.0/16
os_sdn_network_plugin_name='redhat/openshift-ovs-multitenant'

# host group for masters
[etcd]
etcd.ose.com 

[masters]
test.ose.com openshift_hostname=test.ose.com openshift_public_hostname=test.ose.com 

#  host group for nodes, includes region info
[nodes]
test.ose.com openshift_hostname=test.ose.com openshift_public_hostname=test.ose.com openshift_node_labels="{'region': 'infra', 'zone': 'default'}"


---------------

FAIL:
TASK: [docker | Install docker] *********************************************** 
ok: [test.ose.com]
failed: [etcd.ose.com] => {"changed": false, "failed": true, "rc": 0, "results": []}
msg: No Package matching 'docker' found available, installed or updated