core: Fix XBox music browsing
core: Fix XBox music browsing

9aff5d6 was filtering out everything on Album/Artist view on Tracker plugin.

Pelagicore/Media-Manager-Rygel-patched,Tarnyko/rygel,jku/rygel,jku/rygel,GNOME/rygel,GNOME/rygel,Pelagicore/Media-Manager-Rygel-patched,Tarnyko/rygel,GNOME/rygel,Pelagicore/Media-Manager-Rygel-patched