Log Message:
musicpd: update to 0.20.11.

ver 0.20.11 (2017/10/18)
* storage
  - curl: support Content-Type application/xml
* decoder
  - ffmpeg: more reliable song duration
  - gme: fix track numbering
* improve random song order when switching songs manually
* fix case insensitive search without libicu
* fix Unicode file names in playlists on Windows
* fix endless loop when accessing malformed file names in ZIP files