title: express session not updated unless error thrown
body: <p>I am trying to store and update a single var on a sessionCookie. The session object is only updated if i force an error immediately after. If i try to use as documented, the value I set is undefined when I try to access it elsewhere</p>
  
  <p>package:</p>
  
  <pre><code> "dependencies": {
    "express": "3.2.1"
   },
   "engines": {
    "node": "0.10.5",
    "npm": "1.2.18"
   }
  </code></pre>
  
  <p>setup:   </p>
  
  <pre><code>app.use( express.bodyParser() );
  app.use( express.methodOverride() );
  app.use( express.cookieParser('secret') );
  app.use( express.cookieSession(  ) );
  </code></pre>
  
  <p>routes:</p>
  
  <pre><code>module.exports.size = function ( req, res ) {
     req.session["size"] = req.body.size;
     req.s["size"] =  req.body.size; // force to error: this updates session props
  };
  
  module.exports.pages = function ( wwwPath, imageEndPoint, isDebug ) {
     return  function ( req, res ) {
         var size = req.session["size"] // is undefined unless above forced to error
     }
  }
  </code></pre>