Use default interface name in dhclient.conf.

Instead of hardcoding to eth0.

playbooks/roles/vhost/templates/etc/dhcp/dhclient.conf.j2

@@ -56,7 +56,7 @@ request subnet-mask, broadcast-address, time-offset, routers,
 #  expire 2 2000/1/12 00:00:01;
 #}
 
-interface "eth0" {
+interface "{{ ansible_default_ipv4.interface }}" {
     prepend domain-search {% for search in COMMON_DHCLIENT_DNS_SEARCH -%}"{{ search }}"{%- if not loop.last -%},{%- endif -%}
 {%- endfor -%};
 }