Remove redundant todo comment

Author: Alec Gibson

lib/backend.js

@@ -132,8 +132,6 @@ Backend.prototype.connect = function(connection, req, callback) {
  * (The agent is available through all middleware)
  */
 Backend.prototype.listen = function(stream, req) {
-  // TODO: When a Connection reconnects with a persisted src, it will change the
-  // Agent's ID to be something different than what it had in the connection middleware
   var agent = new Agent(this, stream);
   this.trigger(this.MIDDLEWARE_ACTIONS.connect, agent, {stream: stream, req: req}, function(err) {
     if (err) return agent.close(err);