Our reviewboard.oauth app had an app label of reviewboard_oauth,

which didn't match any other references to the app. The custom label

affected admin URLs, the label for the app in the database UI (though

this is easily correctable), and some internal machinery of the

oauth2_provider module. This only applied on Django 1.7+, meaning that

we had a major discrepency between 1.6 and newer versions.
To keep things compatible with what we've had in the past, we're going

to continue using an app label of oauth.
We're also lazily importing the method for enabling OAuth2 scopes, in

order to avoid breaking the Django app initialization process.

Unit tests pass on Django 1.6 and 1.11.