Fix compiler warnings uncovered with -Wall


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4755 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/rfb/hextileEncode.h b/common/rfb/hextileEncode.h
index 9f8bd55..0d2e8ab 100644
--- a/common/rfb/hextileEncode.h
+++ b/common/rfb/hextileEncode.h
@@ -69,7 +69,7 @@
 
       GET_IMAGE_INTO_BUF(t,buf);
 
-      PIXEL_T bg, fg;
+      PIXEL_T bg = 0, fg = 0;
       int tileType = TEST_TILE_TYPE(buf, t.width(), t.height(), &bg, &fg);
 
       if (!oldBgValid || oldBg != bg) {