[REJECT] watchmaildir: spam checking and learning improvements

[Eric Wong <e@80x24.org>]

Eric Wong <e@80x24.org> wrote:
> It turns out spam training ("spamc -L spam") was never implemented
> for -watch.  So implement that, and take advantage of an
> existing feature to pass FDs directly to spamc(1) instead of
> reconverting the MIME object into a string.

Will keep that...

> While we're at it, the spam-checking call is now only performed
> once per message when a Maildir supports multiple inboxes.

And that.

> This changes PublicInbox::Import::add (and V2Writable
> equivalent) API to no longer perform spam-checking.

But nope, we need to do spam-checking inside ->add;
because we don't want to waste cycles re-spam-checking
messages which are already in our archives on -watch
restarts.

And the V2Writable->add spam-checking is in the wrong place.