Supress Express deprecation warning in console

Updated res.send -> res.sendStatus in routes/index.js to supress an express deprecation warning found in console.

Steps to replicate problem:

1. atlas-connect new -t hipchat test

2. Run locally and Install add-on

3. /hello in the chat room

4. see deprecation error in console: "express deprecated res.send(status): Use res.sendStatus(status) instead routes/index.js:148:15"