Change a case to EqualityComparer.Default to handle null properly.
Change a case to EqualityComparer.Default to handle null properly.

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