title: Firebase set() callback is not firing
body: <pre><code>var data = {name:"test", age:20};
  var ref = new Firebase('http://test.firebaseio.com');
  ref.set(data, function(error){
   // Callback comes here
   if(error){
      console.log(error);
   }
   else{
      console.log("Data successfully");
    }
  
  });
  </code></pre>
  
  <p>But the callback is not firing at all but it is inserting in the database</p>