sync machine password to keytab: handle FreeIPA use case

sync machine password to keytab: handle FreeIPA use case

FreeIPA uses own procedure to retrieve keytabs and during the setup of
Samba on FreeIPA client the keytab is already present, only machine
account needs to be set in the secrets database.

'sync machine password to keytab' option handling broke this use case by
always attempting to contact a domain controller and failing to do so
(Fedora bug https://bugzilla.redhat.com/show_bug.cgi?id=2309199).

The original synchronizing machine account password to keytab feature
did not have a mechanism to disable its logic at all.

Signed-off-by: Alexander Bokovoy <ab@samba.org>
Reviewed-by: Pavel Filipenský <pfilipensky@samba.org>
Autobuild-User(master): Alexander Bokovoy <ab@samba.org>
Autobuild-Date(master): Fri Sep 13 13:16:09 UTC 2024 on atb-devel-224