Clear mAudioRecord and mAudioTrack on set() failure

Bug: 20818955
Bug: 20890069
Change-Id: I243205b99b198eb1b5a1a027b27cbb7d5aaaa8db
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index 891a9e9..efbc0d6 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1628,6 +1628,7 @@
         if ((t == 0) || (t->initCheck() != NO_ERROR)) {
             ALOGE("Unable to create audio track");
             delete newcbd;
+            // t goes out of scope, so reference count drops to zero
             return NO_INIT;
         } else {
             // successful AudioTrack initialization implies a legacy stream type was generated