Don't return None on mismatched interactive passwords
    
    This will cause the command to continue with no password set
    at all which is not what we want.
    
    We want to loop forever until the passwords match or the
    user gives up and types ^D or ^C.
    
    https://pagure.io/freeipa/issue/7383
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>