Fix click sound at the end of tts playing.
Fix click sound at the end of tts playing.

Change-Id: I6f69f4c42b2a54db8903d082c59b7cd35c241282

google/aiyprojects-raspbian,google/aiyprojects-raspbian,google/aiyprojects-raspbian,google/aiyprojects-raspbian,google/aiyprojects-raspbian