[droid-sink] Workaround use OUT_SPEAKER as default device.

AUDIO_DEVICE_OUT_DEFAULT is defined as AUDIO_DEVICE_BIT_DEFAULT instead
of real output device. Use OUT_SPEAKER as default output so that default
opens working routing.
Merge pull request #3 from jusa/i9305-fix

[droid-sink] Workaround use OUT_SPEAKER as default device.