[gnome-panel/gnome-3-30] toplevel: fix discarded-qualifiers warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 5bc35bae2d651da96ed4fafbfff02875de2abef1
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Wed Sep 12 21:06:51 2018 +0300

    toplevel: fix discarded-qualifiers warning

 gnome-panel/panel-toplevel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gnome-panel/panel-toplevel.c b/gnome-panel/panel-toplevel.c
index 017777c1d..4365a0c78 100644
--- a/gnome-panel/panel-toplevel.c
+++ b/gnome-panel/panel-toplevel.c
@@ -2123,7 +2123,7 @@ calculate_minimum_height (GtkWidget        *widget,
 {
        GtkStateFlags     state;
        GtkStyleContext  *style_context;
-        const PangoFontDescription *font_desc;
+       PangoFontDescription *font_desc;
        PangoContext     *pango_context;
        PangoFontMetrics *metrics;
        GtkBorder         padding;