Spotify integration with the sound menu

[pachulo]

OK, I just found that is a known issue:

• Mpris support on 16.04 missing?
• https://bugs.launchpad.net/snappy/+bug/1604887

Right now, executing this:
sudo mv /var/lib/snapd/desktop/applications/spotify_spotify.desktop /var/lib/snapd/desktop/applications/spotify.desktop

Acts as a workaround.