Handle more password reset edge cases:

[rjsparks]

IntegrityError at /accounts/reset/

duplicate key value violates unique constraint "auth_user_username_key"
DETAIL:  Key (username)=(some username)

When automatically repairing broken accounts, the code is not yet looking correctly for disconnected users (or users that might be connected to another Person). Both of those will probably require a message to the user that says "help is on the way" and a message to an admin that indicates a disconnected user or a possible duplicate person.