Add a 'release' method to the SurfaceTexture public Java API

Bug: 5063618
Change-Id: I689cb0c01c14e597ccfb4eb0972e64fa570bd4e8
diff --git a/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index 4f51f03..1a036ee 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -910,6 +910,7 @@
     Mutex::Autolock lock(mMutex);
     freeAllBuffers();
     mAbandoned = true;
+    mCurrentTextureBuf.clear();
     mDequeueCondition.signal();
 }