Re: [PATCH 08/13] tmp-objdir: manage quarantine as an object directory

> When creating a quarantine directory via the "tmp-objdir" subsystem we
> create a new "files" backend that new objects part of the transaction
> can be written to. In a future commit though we'll move handling of
> alternates into the "files" backend, and as part of that it will no
> longer be possible for us to have multiple sources attached to a single
> object database.

> In a preceding commit, we have prepared the "files" backend to be able
> to handle multiple object directories. We don't use that mechanism for
> alternates yet, but will start doing so in a subsequent commit. But with
> that infrastructure ready we can already migrate tmp-objdirs over to use
> this new mechanism.
>
> Adapt the subsystem so we create a `struct odb_files_dir` instead of a
> new "files" source.
>
> Signed-off-by: Patrick Steinhardt <ps@pks.im>