Added missing argument

Added missing 'next' argument to the '/_session' route callback

lib/index-api.js

@@ -100,7 +100,7 @@ module.exports = function(config, auth, storage) {
 
   // placeholder 'cause npm require to be authenticated to publish
   // we do not do any real authentication yet
-  app.post('/_session', Cookies.express(), function(req, res) {
+  app.post('/_session', Cookies.express(), function(req, res, next) {
     res.cookies.set('AuthSession', String(Math.random()), {
       // npmjs.org sets 10h expire
       expires: new Date(Date.now() + 10*60*60*1000)