s3: libsmb/namequery: fallback to returning all dcs, when none is available in the...

s3: libsmb/namequery: fallback to returning all dcs, when none is available in the requested site

It could happen that all dcs in a site are unavailable
(some sites have only one dc) and then we need to fallback
to get all dcs.

metze

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Günther Deschner <gd@samba.org>
(cherry picked from commit c127367b1dd622eeceb1f47de0a047c297dda222)
(cherry picked from commit 0c43f96330f2935805ba4f0f8f858a027a90bc4c)
(cherry picked from commit caaf59383ceabdc555f7db098dae0455dea65023)