selftest/drs: Demonstrate ERROR(ldb): uncaught exception - Deleted target CN=NTDS...

selftest/drs: Demonstrate ERROR(ldb): uncaught exception - Deleted target CN=NTDS Settings... in join

"samba-tool domain join" uses the replication API in a strange way, perhaps no longer
required, except that we often still have folks upgrading from very old Samba versions.

By deferring the writing out to the DB of link replication to the very end, we have a
better chance that all the objects required are present, however the situation may
have changed during the cycle, and a link could still be sent, pointing to a deleted
object.

We currently fail in this situation.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15329

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>
(cherry picked from commit 2d41bcce83a976b85636c92d6fc38c63fdde5431)