minidlna: update to version 1.2.1

1.2.1 - Released 24-Aug-2017
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- Added Movian client detection and subtitle support.
- Fixed an issue with discovery on non-Linux systems.
- Fixed Bonjour discovery compatibility with TiVo Bolt.
- Fixed NFO file parsing, and added change monitoring support for them.
- Added a workaround for video thumbnails on some Samsung clients.
- Added DoS protection for event subscriptions.
- Fixed content browsing issues with some Samsung TVs.
- Improved non-destructive update scan support.

Signed-off-by: James Christopher Adduono <jc@adduono.com>