use dns_jail_enabled for dnsmasq blackhole

roles/network/templates/network/dnsmasq.conf.j2

@@ -4,7 +4,7 @@ bogus-priv
 #server=/{{ iiab_domain }}/{{ iiab_hostname }}
 # Add local-only domains here, queries in these domains are answered　from /etc/hosts or DHCP only.
 local=/{{ iiab_domain }}/
-{% if captive_portal_enabled == "True" %}
+{% if dns_jail_enabled %}
 # Make all host names resolve to the Raspberry Pi's IP address
 address=/#/{{ lan_ip }}
 {% endif %}