After failing to create an AudioTrack, only stop the source if we were the ones starting it.

Change-Id: I1820c2634cfeb01af9eaf11b6473c5d7b87d1fa3
related-to-bug: 2716035
diff --git a/media/libstagefright/AudioPlayer.cpp b/media/libstagefright/AudioPlayer.cpp
index bcf2463..b79ba13 100644
--- a/media/libstagefright/AudioPlayer.cpp
+++ b/media/libstagefright/AudioPlayer.cpp
@@ -87,7 +87,9 @@
                 DEFAULT_AUDIOSINK_BUFFERCOUNT,
                 &AudioPlayer::AudioSinkCallback, this);
         if (err != OK) {
-            mSource->stop();
+            if (!sourceAlreadyStarted) {
+                mSource->stop();
+            }
 
             return err;
         }
@@ -108,7 +110,9 @@
             delete mAudioTrack;
             mAudioTrack = NULL;
 
-            mSource->stop();
+            if (!sourceAlreadyStarted) {
+                mSource->stop();
+            }
 
             return err;
         }