LGTM: raise handle_not_found()
    
    Turn calls "handle_not_found()" into "raise handle_not_found()" to
    indicate control flow chance. It makes the code easier to understand,
    the control flow more obvious and helps static analyzers.
    
    It's OK to raise here because handle_not_found() always raises an
    exception.
    
    https://pagure.io/freeipa/issue/7344
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>