hwc: Fix klockwork errors

Resolving klockwork errors to avoid memory leaks,
improper assignments in liboverlay.

Change-Id: I82ac6ae782c7b783e89999b832bbd1d361376b9f
diff --git a/libhwcomposer/hwc_copybit.cpp b/libhwcomposer/hwc_copybit.cpp
index d7afa19..f379cf8 100644
--- a/libhwcomposer/hwc_copybit.cpp
+++ b/libhwcomposer/hwc_copybit.cpp
@@ -811,7 +811,7 @@
 }
 
 CopyBit::CopyBit(hwc_context_t *ctx, const int& dpy) : mIsModeOn(false),
-        mCopyBitDraw(false), mCurRenderBufferIndex(0) {
+        mCopyBitDraw(false), mCurRenderBufferIndex(0), mEngine(0) {
 
     getBufferSizeAndDimensions(ctx->dpyAttr[dpy].xres,
             ctx->dpyAttr[dpy].yres,