docs: mopidy.audio.Audio docs broken

[tkem]

Starting with release-2.0: http://mopidy.readthedocs.org/en/release-2.0/api/audio/.

[adamcik]

Is alias of <Mock object at 0x7fbb512530d0> the problem you had in mind?

[tkem]

Yes. I guess I should be more explicit in my issue reports ;-)

[jodal]

This is also partly responsible for the mopidy package build not being fully reproducible in Debian, ref. https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/diffoscope-results/mopidy.html