fix [3389263] OMX.Nvidia.h264.decode fails to shutdown

We were still destroying an ANativeWindow's buffer pretty soon
after it was removed from the window manager. This time
we really wait for the ISurace to go away.

Change-Id: I329273fedaeef76ee92836f6180c2c3808389330
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 3730739..f64fd7b 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -150,8 +150,7 @@
     // the layer is not on screen anymore. free as much resources as possible
     mFreezeLock.clear();
 
-    EGLDisplay dpy(mFlinger->graphicPlane(0).getEGLDisplay());
-    mBufferManager.destroy(dpy);
+    // Free our own reference to ISurface
     mSurface.clear();
 
     Mutex::Autolock _l(mLock);