Remove warning when non-recognized ACME URLs are received

When retrieving ACME URLs from the LE staging server, LE will respond
with random entries as described in
https://community.letsencrypt.org/t/adding-random-entries-to-the-directory/33417.
The official guideline is that any unrecognized entries should be
ignored, so this warning should be removed.

lib/get-acme-urls.js

@@ -39,11 +39,6 @@ module.exports.create = function (deps) {
         }
       }
 
-      if (5 !== Object.keys(data).length) {
-        console.warn("This Let's Encrypt / ACME server has been updated with urls that this client doesn't understand");
-        console.warn(data);
-      }
-
       if (!knownUrls.every(function (url) {
         return data[url];
       })) {