s3:smbd: disable "vfs mkdir use tmp name = auto" on OpenBSD

s3:smbd: disable "vfs mkdir use tmp name = auto" on OpenBSD

This is the simplest way to avoid a regression.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15801

Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>

Signed-off-by: Ralph Boehme <slow@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Wed Mar  5 12:37:40 UTC 2025 on atb-devel-224

(cherry picked from commit a3f129f66346dcec41a01caf8060fe1a9da484ac)

Autobuild-User(v4-22-test): Jule Anger <janger@samba.org>
Autobuild-Date(v4-22-test): Wed Mar  5 15:13:18 UTC 2025 on atb-devel-224