Removing unwanted user/pass for auth

lib/adapters/http.js

@@ -49,8 +49,8 @@ module.exports = function httpAdapter(resolve, reject, config) {
   // HTTP basic authentication
   var auth = undefined;
   if (config.auth) {
-    var username = config.auth.user || config.auth.username;
-    var password = config.auth.pass || config.auth.password;
+    var username = config.auth.username || '';
+    var password = config.auth.password || '';
     auth = username + ':' + password;
   }