Fix BeatmapSetInfos with OnlineBeatmapSetID set to null being marked as downloaded.
Fix BeatmapSetInfos with OnlineBeatmapSetID set to null being marked as downloaded.

ppy/osu,EVAST9919/osu,UselessToucan/osu,UselessToucan/osu,smoogipoo/osu,DrabWeb/osu,NeoAdonis/osu,2yangk23/osu,EVAST9919/osu,ppy/osu,johnneijzen/osu,smoogipoo/osu,ZLima12/osu,naoey/osu,DrabWeb/osu,ppy/osu,UselessToucan/osu,naoey/osu,peppy/osu-new,smoogipooo/osu,ZLima12/osu,NeoAdonis/osu,2yangk23/osu,DrabWeb/osu,smoogipoo/osu,peppy/osu,peppy/osu,naoey/osu,johnneijzen/osu,peppy/osu,NeoAdonis/osu