The original intention was to retrieve the first available user in auth.get_backends(). However, if an exception happens in the try clause, it goes to the except which passes and then the variable "user" is not initialized. The function get_or_create_user either returns an actual user, None, or throws exception. 
I found this when I was working on this (https://reviews.reviewboard.org/r/3242/). I was waiting on code review a year ago but just slipped out of radar. I've been cleaning that one year old branch but I need more time to fix up some ugly merges, redo some parts due  to being so out of date and testing etc...

Manual testing