Not related, but proxy now has a is_tombstone flag that should probably be used here and in new_kd_entry_list/update_kd_entry_list used below. I need to see if all of that code is consistent with the new tombstone flagging.  Also, at some point I think we should switch to flagging tombstones like Scott did for the hintfiles, using a bit in the offset field. That way we could leave them pointing to the actual tombstone on file if that ever becomes helpful.