Reset compositionType to HWC_FRAMEBUFFER before calling prepare()

Honor the documentation. this broke in JB-MR1.

Change-Id: I841a93b409fc940374bc748c4e143d82a192669c
diff --git a/services/surfaceflinger/LayerBase.cpp b/services/surfaceflinger/LayerBase.cpp
index db4ef87..9b03c74 100644
--- a/services/surfaceflinger/LayerBase.cpp
+++ b/services/surfaceflinger/LayerBase.cpp
@@ -300,6 +300,7 @@
 
 void LayerBase::setPerFrameData(const sp<const DisplayDevice>& hw,
         HWComposer::HWCLayerInterface& layer) {
+    layer.setPerFrameDefaultState();
     // we have to set the visible region on every frame because
     // we currently free it during onLayerDisplayed(), which is called
     // after HWComposer::commit() -- every frame.