CONFDB: Start a ldb transaction from sss_ldb_modify_permissive()
    
    The reason why confdb_expand_app_domains() always fails is because we
    try to do a ldb_request() without starting a ldb transaction.
    
    When we're dealing with ldb_modify(), ldb_add(), ldb_delete() kind of
    messages, those call ldb_autotransaction_request() which will start a
    new transaction and treat it properly when doing the ldb_request(). In
    our case that we're calling ldb_request() by our own, we must ensure
    that the transaction is started and properly deal with it._
    
    It's never been noticed because in the only place the function is used
    its errors are ignored.
    
    Resolves:
    https://pagure.io/SSSD/sssd/issue/3660
    
    Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>