fix Corrupted graphics while playing You Tube on orientation change

Bug: 5432124
Change-Id: If948b9797b1ec6fff80ca5ea94508abcaced9f31
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e869ba2..a6d4147 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1784,8 +1784,10 @@
     // redraw the screen entirely...
     glDisable(GL_TEXTURE_EXTERNAL_OES);
     glDisable(GL_TEXTURE_2D);
+    glDisable(GL_SCISSOR_TEST);
     glClearColor(0,0,0,1);
     glClear(GL_COLOR_BUFFER_BIT);
+    glEnable(GL_SCISSOR_TEST);
     glMatrixMode(GL_MODELVIEW);
     glLoadIdentity();
     const Vector< sp<LayerBase> >& layers(mVisibleLayersSortedByZ);