Query flexible attributes already in _fetch()
Query flexible attributes already in _fetch()

This resolves the query length and potential security problems,
while keeping the performance benefits.

sampsyo/beets,ibmibmibm/beets,sampsyo/beets,shamangeorge/beets,SusannaMaria/beets,beetbox/beets,jackwilsdon/beets,SusannaMaria/beets,sampsyo/beets,ibmibmibm/beets,ibmibmibm/beets,sampsyo/beets,SusannaMaria/beets,jackwilsdon/beets,SusannaMaria/beets,ibmibmibm/beets,beetbox/beets,beetbox/beets,beetbox/beets,jackwilsdon/beets,shamangeorge/beets,jackwilsdon/beets,shamangeorge/beets,shamangeorge/beets