After commit 1afa33c3c766af2, an old bug was revealed:
SimpleDatabase::GetSong() constructs an ExportedSong instance by
moving the return value of Song::Export(), which causes the
LightSong::tag field to be dangling on the moved-from
ExportedSong::tag_buffer. This broke tags from CUE sheets.
Closes https://github.com/MusicPlayerDaemon/MPD/issues/1070
d4d06da2f8