Log Message:
cups-filters: updated to 1.21.6

CHANGES IN V1.21.6
- cups-browsed: To find out whether a DNS-SD-discovered
  printer is from the local machine, use not only the flags in
  the Avahi lookup result but also check the host name.
- cups-browsed: When a local CUPS queue pointing to a remote
  CUPS printer was removed and re-created to make it a
  permanent queue, on_printer_deleted() was triggered by
  cupsd's notification to re-create a lost queue. Now
  on_printer_deleted() checks whether the queue is really gone
  and only re-creates then.
- cups-browsed: When updating the CUPS queues, also removed
  and unregistered queues and not only created queues got
  checked for HTTP timeouts, which caused crashes on shutdown.
- pdftops: Use the PS interpreter of Poppler for all Apple
  LaserWriter 16/600, 4/600, 12/640, 12/600, 12/660 as they
  all seem to not work with Ghostscript's PS output.
- cups-browsed: On shutdown queues got removed even if they
  still had jobs