do not overwrite creation of res.locals

lib/cartodb/middleware/context/layergroup-token.js

@@ -1,7 +1,7 @@
 var LayergroupToken = require('../../models/layergroup-token');
 
 module.exports = function layergroupTokenMiddleware(req, res, next) {
-    if (!res.locals.hasOwnProperty('token')) {
+    if (!res.locals.token) {
         return next();
     }
 

lib/cartodb/server.js

@@ -369,8 +369,6 @@ function bootstrap(opts) {
     app.use(bodyParser.json());
 
     app.use(function bootstrap$prepareRequestResponse(req, res, next) {
-        res.locals = {};
-        
         req.profiler = new Profiler({
             statsd_client: global.statsClient,
             profile: opts.useProfiler