Fastboot collision when running tests

[davidlormor]

Just forked the repo and ran the tests. Get the following error:

Build failed.
File: modules/ember-data/adapter.js
The Broccoli Plugin: [Babel] failed with:
ReferenceError: The plugin "babel-plugin-feature-flags" collides with another of the same name at PluginManager.validate (/Users/davidlormor/Development/GitHub/ember-power-select/node_modules/babel-core/lib/transformation/file/plugin-manager.js:159:13)

Seems like this is related to:

• [BUGFIX release] Only setup babel options once. emberjs/data#4328
• babel-plugin-feature-flags name collision in 2.5.1 with fastboot emberjs/data#4322

Sounds like the addition of fastboot may be causing the issue in Ember Data - running against canary seems to solve the issue.

[cibernox]

Closes by #454