Milter-greylist

> The attachment does not exist on the server.
It is normally a problem with the yahoo server.
That may become visible after a while.

By the way this patch is not really solves the problem,
only partially. The second problem is that the "pending"
list is referenced only in the sync queue, not copied.
After calling peer_delete() the pending_put()
immediately updates the  values of the same
structure. The data is read later in another thread
to send to the peers.