Fix error that causes googlebot accessing url /practice as Lazy user

[jirmauritz]

Every time googlebot access our system (apx. every 3 days), the top level exception is thrown as django refuses to process SimpleLazy object instead of real user.

Error:
https://groups.google.com/d/msg/adaptive-programming-errors/D0N5nmt8_zo/AhGQT3M0AgAJ