taglib: downgrade to taglib-1.8, this should solve crashes on flac files with IDv2 tags (see http://openelec.tv/forum/74-music-management/71780-crash-when-adding-folder-to-music-library#115179 and https://github.com/taglib/taglib/issues/416)

Signed-off-by: Stephan Raue <stephan@openelec.tv>