Ensured the hashed password is unicode
    
    Otherwise it is returned as bytes which is stored in postgresql
    incorrectly leading to failure to login (while registering works
    just fine).
    
    Fixes https://pagure.io/pagure/issue/3491
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr></pingou@pingoured.fr>