am c8aa837a: Don\'t let untranslated "<unknown>" or "null" be displayed in Music.

Merge commit 'c8aa837a48287ad94ee0dcacb525b420a908a06d'

* commit 'c8aa837a48287ad94ee0dcacb525b420a908a06d':
  Don't let untranslated "<unknown>" or "null" be displayed in Music.