SF: Initialize mSingleBufferMode

Bug 25586311

Change-Id: I2d66542c6ecb762924fa002e5487188703be8515
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index ad53226..1c2c05d 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -86,7 +86,8 @@
         mQueueItemCondition(),
         mQueueItems(),
         mLastFrameNumberReceived(0),
-        mUpdateTexImageFailed(false)
+        mUpdateTexImageFailed(false),
+        mSingleBufferMode(false)
 {
     mCurrentCrop.makeInvalid();
     mFlinger->getRenderEngine().genTextures(1, &mTextureName);