net/upnp: replace obsolete find_interface_ip()

PR: https://github.com/opnsense/core/issues/4749

net/upnp/Makefile

@@ -1,6 +1,6 @@
 PLUGIN_NAME=		upnp
 PLUGIN_VERSION=		1.4
-PLUGIN_REVISION=	1
+PLUGIN_REVISION=	2
 PLUGIN_DEPENDS=		miniupnpd
 PLUGIN_COMMENT=		Universal Plug and Play Service
 PLUGIN_MAINTAINER=	franco@opnsense.org

net/upnp/src/etc/inc/plugins.inc.d/miniupnpd.inc

@@ -148,9 +148,8 @@ function miniupnpd_configure_do($verbose = false)
             $if = get_real_interface($iface);
             /* above function returns iface if fail */
             if ($if != $iface) {
-                $addr = find_interface_ip($if);
-                /* check that the interface has an ip address before adding parameters */
-                if (is_ipaddr($addr)) {
+                list ($addr) = interfaces_primary_address($iface);
+                if (!empty($addr)) {
                     $config_text .= "listening_ip={$if}\n";
                     if (!$ifaces_active) {
                         $webgui_ip = $addr;