Fix breaking changes in FastBoot 1.0

[simonihmig]

The current ember-cli-fastboot releases (1.0.0-rc.1 and above) introduce breaking changes. These will most likely break your current FastBoot implementation.

See https://github.com/ember-fastboot/ember-cli-fastboot/issues/387 for more information and a guide on how to fix your addon. Also you may want to visit the -fastboot Slack channel to get help from other users.

Note: this issue has been created automatically, by searching for certain patterns in your code. If you think this has been falsely created, feel free to close!