If the user doesn't have a valid ssh key inform and keep doing
    
    There are a few situation where set_up_user will raise an exception
    if this exception is due to an invalid ssh key provided, we should
    just inform the user about it and let them log in, otherwise, let's
    raise the error, catch it later and inform the user then.
    
    Fixes https://pagure.io/pagure/issue/4303
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr></pingou@pingoured.fr>