MPD: Fix Album Artist setting regression from 51cecb7.
MPD: Fix Album Artist setting regression from 51cecb7.

Second attempt to fix this one.

hurzl/dmix,0359xiaodong/dmix,0359xiaodong/dmix,jcnoir/dmix,jcnoir/dmix,abarisain/dmix,hurzl/dmix,joansmith/dmix,joansmith/dmix,abarisain/dmix