Force artist index values

[simoncn]

The setting AlbumArtist:nil means that MinimServer will not read any AlbumArtist tags from your files. It sound like the LUMIN app is using previously cached AlbumArtist information from before you added the AlbumArtist:nil setting. If you reload your MinimServer library into the LUMIN app, you should no longer see AlbumArtist information there.