Squashed 'luci-app-smartdns/' changes from 26e7e29..d6163f5

d6163f5 chore(i18n): Update PO files
751827d luci: add `-fallback` option to upstream dns server

git-subtree-dir: luci-app-smartdns
git-subtree-split: d6163f5fccb4e72e95632738678e5b9ab1df2454

htdocs/luci-static/resources/view/smartdns/smartdns.js

@@ -1038,6 +1038,13 @@ return view.extend({
 			return true;
 		}
 
+		// fallback
+		o = s.taboption("advanced", form.Flag, "fallback", _("Fallback"),
+			_("Mark this server as a fallback server, use it only when default servers fail."))
+		o.default = o.disabled
+		o.rmempty = true
+		o.modalonly = true    
+
 		// other args
 		o = s.taboption("advanced", form.Value, "addition_arg", _("Additional Server Args"),
 			_("Additional Args for upstream dns servers"))