MediaPlayer: trigger onError instead of exception on stale native notifications

This change also reverted commit 2c838fbd87ad5685c0008b419ea02421159b9b70,
"MediaPlayer: add mPreparing to weed out unwanted prepared messages".

Bug: 21266735
Change-Id: I392342519420bee2fde1fe1915c51d24101ca27d
diff --git a/media/jni/android_media_MediaPlayer.cpp b/media/jni/android_media_MediaPlayer.cpp
index 9c67278..d8041f4 100644
--- a/media/jni/android_media_MediaPlayer.cpp
+++ b/media/jni/android_media_MediaPlayer.cpp
@@ -1045,7 +1045,7 @@
     {"_setDataSource",      "(Landroid/media/MediaDataSource;)V",(void *)android_media_MediaPlayer_setDataSourceCallback },
     {"_setVideoSurface",    "(Landroid/view/Surface;)V",        (void *)android_media_MediaPlayer_setVideoSurface},
     {"_prepare",            "()V",                              (void *)android_media_MediaPlayer_prepare},
-    {"_prepareAsync",       "()V",                              (void *)android_media_MediaPlayer_prepareAsync},
+    {"prepareAsync",        "()V",                              (void *)android_media_MediaPlayer_prepareAsync},
     {"_start",              "()V",                              (void *)android_media_MediaPlayer_start},
     {"_stop",               "()V",                              (void *)android_media_MediaPlayer_stop},
     {"getVideoWidth",       "()I",                              (void *)android_media_MediaPlayer_getVideoWidth},