Don't use sp<>&

because they may end up pointing to NULL after a NULL check was performed.

Bug: 28166152
Change-Id: Iab2ea30395b620628cc6f3d067dd4f6fcda824fe
diff --git a/media/libmedia/IMediaDeathNotifier.cpp b/media/libmedia/IMediaDeathNotifier.cpp
index d4360ea..c43ef66 100644
--- a/media/libmedia/IMediaDeathNotifier.cpp
+++ b/media/libmedia/IMediaDeathNotifier.cpp
@@ -31,7 +31,7 @@
 SortedVector< wp<IMediaDeathNotifier> > IMediaDeathNotifier::sObitRecipients;
 
 // establish binder interface to MediaPlayerService
-/*static*/const sp<IMediaPlayerService>&
+/*static*/const sp<IMediaPlayerService>
 IMediaDeathNotifier::getMediaPlayerService()
 {
     ALOGV("getMediaPlayerService");