Retry chronyc waitsync only once
    
    It's unlikely that a third chrony synchronization attempt is going to
    succeed after the the first two attempts have failed. Perform more
    retries with smaller timeout.
    
    This speed up installer by 11 seconds on systems without fully
    configured chronyd or no chronyd (e.g. containers).
    
    Related: https://pagure.io/freeipa/issue/8521
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Francois Cami <fcami@redhat.com>