Fixes an issue with captive portal handler

DNSMASQ was sending requests to the captive portal URL interface,
but the PHP script was not allowed to be executed.

piratebox/piratebox/conf/lighttpd/captive_portal.conf

@@ -18,7 +18,7 @@ $HTTP["url"] =~ "^/connecttest.txt" {
         server.error-handler-404 = "/captive/ia_handler.php"
 }
 
-$HTTP["url"] =~ "^/captive/ia_handler.php$" {
+$HTTP["url"] =~ "^/captive/" {
         fastcgi.server = (
                 "" => ((
                                 "bin-path" => "/usr/bin/php-cgi",