[PATCH] idmap_ad: Retry query_user exactly once if we get TLDAP_SERVER_DOWN

[Ralph Böhme]

On Fri, Jun 30, 2017 at 04:10:01PM -0700, Dustin L. Howett via samba-technical wrote:
> All other ldap-querying methods in idmap_ad make a single retry attempt if they get
> TLDAP_SERVER_DOWN. This patch brings idmap_ad_query_user in line with that design.
> 
> This fixes the symptom described in 12720 at the cost of an additional reconnect per
> failed lookup.

lgtm. Can I get a second reviewer?

Cheerio!
-slow