Stable release triggers deprecation warnings in 2.7.0

Hi !

I have an issue with this addon when i try to install directly i get:

```
> ember install ember-collection
DEPRECATION: Overriding init without calling this._super is deprecated. Please call `this._super.init && this._super.init.apply(this, arguments);` addon: `ember-cli-htmlbars`
at Function.Addon.lookup (/Users/hugoruscitti/proyectos/huayra/huayra-stopmotion/node_modules/ember-cli/lib/models/addon.js:1009:27)
Installed packages for tooling via npm.
```

but installing alpha.6 seems to work, it's normal to specify this version for new projects? or there are any other workaround?

```
> ember install ember-collection@1.0.0-alpha.6
```