Bug Description:  The server was previously reserving the backend
                  name "default".  If you tried to import on a
                  backend with this name the import would skip all
                  child entries

Fix Description:  Change the default backend name to something
                  obscure, instead of "default".

                  Also improved lib389's dbgen to generate the
                  correct "dc" attribute value in the root node.

https://pagure.io/389-ds-base/issue/49830

Reviewed by: spichugi(Thanks!)