Fixes invalid JSON request body

I am using Kensa with Node.js and Express. With the latest Express/Connect, I am unable to add an app-wide `bodyParser`, e.g.

``` javascript
app.configure(function() {
  app.use(express.bodyParser());
})
```

This is because the test suite's `DELETE` requests use a `Content-Type: application/json` header and no body. Express (and ultimately Connect) sees this request header and attempts to parse with `JSON.parse` which fails with an empty string (not valid JSON).

The current [kensa-create-node](https://github.com/heroku/kensa-create-node) bypasses this issue by adding the `express.bodyParser()` middleware to just `POST` and `PUT` routes. Not an ideal solution for a large project with a few pieces of middleware per route.

**This pull request should resolve the issue, though I am unsure of how the `DELETE` request is implemented in Heroku's addon provisioning itself.**

Also fixed a misnamed test.