(firewall, nat) change default for none to empty,...

(firewall, nat) change default for none to empty, https://github.com/opnsense/core/commit/610013dcf37590350b7e41a32eaaccda08aa09ac#commitcomment-17585636

src/etc/inc/filter.inc

@@ -1945,7 +1945,7 @@ function filter_nat_rules_generate(&$FilterIflist)
                     $localport = "";
                     break;
             }
-            $address_family = !empty($rule['ipprotocol']) ? $rule['ipprotocol'] : "inet";
+            $address_family = !empty($rule['ipprotocol']) ? $rule['ipprotocol'] : "";
 
             $target = alias_expand($rule['target']);
             if (!$target && !isset($rule['nordr'])) {