Update app blueprint's package.json to depend on ember-data directly

Once https://github.com/emberjs/data/pull/2238 is merged and a release published in npm we can swap out `ember-cli-ember-data`.

I'm not sure if we want to depend directly on an exact beta version, i.e. `1.0.0-beta.9` and keep updating it or if we should just use `1.0.0` so it'll auto install the latest beta?