winbindd: avoid multiple wbint_LookupSids/lsa_LookupSids calls to the same domain

winbindd: avoid multiple wbint_LookupSids/lsa_LookupSids calls to the same domain

find_lookup_domain_from_sid() returns the same domain for all non local
sids on a domain member. We should not chunk one wb_lookupsids_send/recv
into multiple wbint_LookupSids_send/recv to the same 'lookup' domain,
just because the requested SIDs don't all belong to the same domain.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Sun Mar 12 00:56:14 CET 2017 on sn-devel-144