Fix: Can't control Alarm/Ring volume after plugout headset and a2dp

1) wired headset is plugin, a2dp is connected, fm is on =>
2) plugout wired headset, then disconnect a2dp =>
3) will not control alarm/ring volume via +/- button
reason: after plugout wired headset, then disconnect a2dp at last,
configureAudioDataPath(true) will be called and AudioSystem.DEVICE_OUT_FM
will be set to DEVICE_STATE_AVAILABLE. Then we can only control
media volume via +/- button.

Change-Id: Ic9b0bad141a8d5d88e6b9b93350a5b02961b91db
CRs-Fixed: 1047328