use ip for etcd proxies even when hostnames are used in the inventory

roles/etcd/templates/etcd2-environment.j2

@@ -15,6 +15,6 @@ ETCD_LISTEN_CLIENT_URLS="http://{{ hostvars[inventory_hostname]['ip'] | default(
 ETCD_LISTEN_PEER_URLS="http://{{ hostvars[inventory_hostname]['ip'] | default( ansible_default_ipv4.address)  }}:2380"
 ETCD_NAME="{{ etcd.name }}"
 {% else  %}
-ETCD_INITIAL_CLUSTER="{% for host in groups['etcd'] %}master{{ loop.index|string }}=http://{{ host }}:2380{% if not loop.last %},{% endif %}{% endfor %}"
+ETCD_INITIAL_CLUSTER="{% for host in groups['etcd'] %}master{{ loop.index|string }}=http://{{ hostvars[host]['ip'] | default(hostvars[host]['ansible_default_ipv4']['address']) }}:2380{% if not loop.last %},{% endif %}{% endfor %}"
 ETCD_LISTEN_CLIENT_URLS="http://127.0.0.1:23799"
 {% endif %}