Cookbook attributes for LB subnet and whether to use IPv6

i.e.
* <code>/etc/nginx/conf.d/telize_common.conf</code> <-- always gets installed, has the map size stuff and includes the timezone conf
* <code>/etc/nginx/conf.d/geoip_ipv4_only.conf</code>  <-- gets installed if ipv6? is false, has the 3 geoip_* lines for ipv4-only mode
* <code>/etc/nginx/conf.d/geoip_ipv6.conf</code>  <-- gets installed if ipv6? is true, has the 3 geoip_* lines for ipv6 mode