gmusic plugin: only authenticate when needed
gmusic plugin: only authenticate when needed

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