move use of TEST and CLOUDRON to constants

src/native-dns.js

@@ -5,7 +5,7 @@ exports = module.exports = {
 };
 
 var assert = require('assert'),
-    config = require('./config.js'),
+    constants = require('./constants.js'),
     dns = require('dns'),
     _ = require('underscore');
 
@@ -24,7 +24,7 @@ function resolve(hostname, rrtype, options, callback) {
     options = _.extend({ }, DEFAULT_OPTIONS, options);
 
     // Only use unbound on a Cloudron
-    if (config.CLOUDRON) resolver.setServers([ options.server ]);
+    if (constants.CLOUDRON) resolver.setServers([ options.server ]);
 
     // should callback with ECANCELLED but looks like we might hit https://github.com/nodejs/node/issues/14814
     const timerId = setTimeout(resolver.cancel.bind(resolver), options.timeout || 5000);