Revert "Remove unused variables"

This reverts commit 004758c725.

src/FontFace.h

@@ -24,6 +24,7 @@ class FontFace: public node::ObjectWrap {
     inline cairo_font_face_t *cairoFace(){ return _crFace; }
   private:
     ~FontFace();
+    FT_Face   _ftFace;
     cairo_font_face_t *_crFace;
     static bool _initLibrary;
 };