boot: apply default firewall policy before interface configuration, preventing possible accessibility of local services during the boot process.

Although the risk of misuse is likely rather small, we better drop traffic if we don't know what should be allowed yet. Our default policy should take care of standard loopback behaviour, so the impact of this change should be relatively small.

src/etc/rc.bootup

@@ -88,6 +88,9 @@ system_hostname_configure(true);
 system_hosts_generate(true);
 system_syslog_start(true);
 
+/* apply default policy before interface setup */
+filter_configure_sync(true, false);
+
 interfaces_configure(true);
 
 system_resolvconf_generate(true);