net/upnp: time to stop using get_interface_ip() in plugins

The function is opportunistic and has weird VIP glue which is not
needed in 98% of the code.

net/upnp/Makefile

@@ -1,6 +1,6 @@
 PLUGIN_NAME=		upnp
 PLUGIN_VERSION=		1.5
-PLUGIN_REVISION=	3
+PLUGIN_REVISION=	4
 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

@@ -146,7 +146,7 @@ function miniupnpd_configure_do($verbose = false)
             $if = get_real_interface($iface);
             /* above function returns iface if fail */
             if ($if != $iface) {
-                $addr = get_interface_ip($iface);
+                list ($addr) = interfaces_primary_address($iface);
                 if (!empty($addr)) {
                     $config_text .= "listening_ip={$if}";
                     if (!empty($upnp_config['overridesubnet'])) {