- Added "ipv6only=on" to the IPv6 listen lines in the nginx vhost template to...

- Added "ipv6only=on" to the IPv6 listen lines in the nginx vhost template to avoid "[emerg]: bind() to [::]:80 failed (98: Address already in use)" errors.

server/conf/nginx_vhost.conf.master

 server {
         listen <tmpl_var name='ip_address'>:80;
 <tmpl_if name='ipv6_enabled'>
-        listen [<tmpl_var name='ipv6_address'>]:80;
+        listen [<tmpl_var name='ipv6_address'>]:80 ipv6only=on;
 </tmpl_if>
 		
 <tmpl_if name='ssl_enabled'>
         listen <tmpl_var name='ip_address'>:443 ssl;
 <tmpl_if name='ipv6_enabled'>
-        listen [<tmpl_var name='ipv6_address'>]:443 ssl;
+        listen [<tmpl_var name='ipv6_address'>]:443 ssl ipv6only=on;
 </tmpl_if>
         ssl_certificate <tmpl_var name='document_root'>/ssl/<tmpl_var name='ssl_domain'>.crt;
         ssl_certificate_key <tmpl_var name='document_root'>/ssl/<tmpl_var name='ssl_domain'>.key;