Description of problem:
ectd cluster install fails when differently named network interfaces are used

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

How reproducible:
Customer 

Steps to Reproduce:
Set up to install etcd clusterd on a host with interface "ens192" and another host wiht  "eth02"


Actual results:
fatal: [uslv-dpas-etc04.amgen.com] => {'msg': "AnsibleUndefinedVariable: One or more undefined variables: 'dict object' has no attribute u'ansible_ens192'", 'failed': True}
fatal: [uslv-dpas-etc04.amgen.com] => {'msg': "AnsibleUndefinedVariable: One or more undefined variables: 'dict object' has no attribute u'ansible_ens192'", 'failed': True}
fatal: [aws-dpas-etc06.amgen.com] => {'msg': "AnsibleUndefinedVariable: One or more undefined variables: 'dict object' has no attribute u'ansible_eth0'", 'failed': True}
fatal: [aws-dpas-etc06.amgen.com] => {'msg': "AnsibleUndefinedVariable: One or more undefined variables: 'dict object' has no attribute u'ansible_eth0'", 'failed': True}


Expected results:

Pass

Additional info:
https://github.com/openshift/openshift-ansible/blob/0ded8248eedf3ad1ceac44eac486e83a53960bb5/roles/etcd/templates/etcd.conf.j2#L4-L6