Authentication in the admin should not make any assumptions on valid user names
|Reported by:||jdetaeye||Owned by:||nobody|
|Has patch:||yes||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
When the user authentication with all configured authentication backend fails, the admin application adds some additional checks when the user name contains the character @.
This does't make sense: the admin application can't know what is a valid user name for the backends. For some backends a @ in the user name may well be valid.