DYNDNS: Retry also on timeouts
    
    There is the dyndns_server option that is supposed to make it possible
    for the admin to select a server to update DNS with if the server
    detected by nsupdate does not work. The fallback works OK for the case
    where nsupdate fails with a non-zero return code, but doesn't work
    for the case where nsupdate times out.
    
    This patch extends the retry condition to also fallback to the
    dyndns_server directive if nsupdate return ERR_DYNDNS_TIMEOUT.
    
    Resolves:
    https://pagure.io/SSSD/sssd/issue/3725
    
    Reviewed-by: Fabiano Fidêncio <fidencio@redhat.com>