Code review comment for lp:~michael.nelson/launchpad/443353-api-builds-from-private

I approve the incremental change. As discussed on IRC, I think it may be possible to remove the first find and use the second query to find cases where SourcePackagePublishingHistory.archiveID == Build.archiveID as well as cases where SourcePackagePublishingHistory.archiveID != Build.archiveID. But if not, it's fine to land as-is.