Description of problem:
OpenShift Facts should not be called on all hosts when only a single group is being modified. 

Example when running  	redeploy-etcd-ca.yml or redeploy-etcd-certificates.yml openshift facts is gathered on all node hosts causing the installer to take to much unneed time to redploy etcd certs. 


Version-Release number of the following components:
└──> rpm -q openshift-ansible
openshift-ansible-3.6.173.0.48-1.git.0.1609d30.el7.noarch

└──> rpm -q ansible
ansible-2.4.0.0-5.el7.noarch

└──> ansible --version
ansible 2.4.0.0
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/cloud-user/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, May  3 2017, 07:55:04) [GCC 4.8.5 20150623 (Red Hat 4.8.5-14)]

How reproducible:
100%

Steps to Reproduce:
1. $ ansible-playbook -i <inventory_file> \
    /usr/share/ansible/openshift-ansible/playbooks/byo/openshift-cluster/redeploy-etcd-certificates.yml


Actual results:
Openshift facts gets call 2 times and ran on all nodes listed in hosts file

Expected results:
facts are only run on etcd hosts.