Fix issue 3388775.

Do not select A2DP output for media strategy when it is suspended because
BT SCO is active. Media audio will be routed to speakers or SCO HS
(depending on phone state and activity on stream VOICE_CALL) which is less
confusing than not hearing anything while music progress bar is moving.

Change-Id: Iff8cc1ea9bf9bde0b33035c4d91398db0934b836