Fix issue 1795088       Improve audio routing code

Initial commit for review.
Integrated comments after patch set 1 review.
Fixed lockup in AudioFlinger::ThreadBase::exit()
Fixed lockup when playing tone with AudioPlocyService startTone()
diff --git a/camera/libcameraservice/CameraService.cpp b/camera/libcameraservice/CameraService.cpp
index 97b43a4..e7c1fbb 100644
--- a/camera/libcameraservice/CameraService.cpp
+++ b/camera/libcameraservice/CameraService.cpp
@@ -33,7 +33,6 @@
 #include "CameraService.h"
 
 #include <cutils/atomic.h>
-#include <cutils/properties.h>
 
 namespace android {
 
@@ -199,13 +198,7 @@
 {
     sp<MediaPlayer> mp = new MediaPlayer();
     if (mp->setDataSource(file) == NO_ERROR) {
-        char value[PROPERTY_VALUE_MAX];
-        property_get("ro.camera.sound.forced", value, "0");
-        if (atoi(value)) {
-            mp->setAudioStreamType(AudioSystem::ENFORCED_AUDIBLE);
-        } else {
-            mp->setAudioStreamType(AudioSystem::SYSTEM);            
-        }
+        mp->setAudioStreamType(AudioSystem::ENFORCED_AUDIBLE);
         mp->prepare();
     } else {
         mp.clear();