Duration depends on the selected subsong and thus must be queried after
selecting the subsong. There is no compelling reason to query other
metadata earlier either.

Tested with libopenmpt version: 0.2.8760-beta27
Libopenmpt configure options: --without-ogg --without-vorbis
--without-vorbisfile --without-portaudio --without-portaudiocpp
--without-mpg123 --without-pulseaudio --without-sndfile --without-flac
Signed-off-by: Jörn Heusipp <osmanx@problemloesungsmaschine.de>
Signed-off-by: Josh de Kock <josh@itanimul.li>