Attached is a patch that simplifies wb_lookupsids by
o removing the fallback logic caused every failed lookup to be retried as a
single lookup, and
o fixing the handling of lookups that failed (because the SID was from an unknown
domain) which let us construct a fake lsa_DomainInfo with domain name ""
The former was mostly need to trigger the latter, the latter was needed as
callers like wb_sids2xids we're not dealing with the failed lookups for SIDs
from unknown domains correctly (sid_index in the translated name will is
UINT32_MAX in the response).
Please review & push if happy. Patchset passes (private) autobuild.
Oh, wait! These patches might become prequisite patches for changes dealing with
SID-history Uri's is working on, so we might need to assing a bugnumber to this
patchset so we can backport.