fix uninitialized variable in DisplayHardware

this fixes the issue where the display is all messed-up sometimes.

Change-Id: I20be91b5166bfff0c6d353a777351842c9df8e95
diff --git a/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp b/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp
index af89e9a..51de1da 100644
--- a/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp
+++ b/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp
@@ -73,7 +73,7 @@
 DisplayHardware::DisplayHardware(
         const sp<SurfaceFlinger>& flinger,
         uint32_t dpy)
-    : DisplayHardwareBase(flinger, dpy)
+    : DisplayHardwareBase(flinger, dpy), mFlags(0)
 {
     init(dpy);
 }