LDAP: Improve error treatment from sdap_cli_connect() in ldap_auth
    
    Because we weren't treating the errors coming from
    sdap_cli_connect_recv() properly we ended up introducing a regression in
    the commit add72860c7, related to offline authentication.
    
    From now on, let's properly treat errors coming from auth_connect_send(),
    which were treated before by going offline when be_resolve_server_recv()
    failed, and propagate ETIMEDOUT to the request, thus going offline and
    allowing offline authentication on those cases.
    
    Related:
    https://pagure.io/SSSD/sssd/issue/3451
    
    Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>
    Reviewed-by: Sumit Bose <sbose@redhat.com>