[cairo] Mention reference ownership in scaled font docs.

[Chris Wilson]

On Tue, 01 Jan 2013 12:46:11 +0100, Simon Sapin <simon.sapin at exyr.org> wrote:
> Hi,
> 
> A tiny fix for the documentation:
> 
> 
> For cairo_scaled_font_get_font_face(), add:
> 
> > This object is owned by cairo. To keep a reference to it, you must call cairo_font_face_reference().

A very sensible suggestion, applied.  Thanks,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre