[gtk+] Fix dobule border rendering

[Matthias Clasen <matthiasc src gnome org>]

commit 12bc8ddb934f76396b070b9aeb47346e62cc70a5
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Jan 9 14:36:05 2016 -0500

    Fix dobule border rendering
    
    This is the same fix that was applied for ridge and groove
    style in 9f27ee7f5abf49a20ac95d57b306ecd4294b49c6.

 gtk/gtkrenderborder.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkrenderborder.c b/gtk/gtkrenderborder.c
index 213d65e..22452d1 100644
--- a/gtk/gtkrenderborder.c
+++ b/gtk/gtkrenderborder.c
@@ -630,7 +630,7 @@ render_border (cairo_t       *cr,
                 else
                   dont_draw |= (1 << j);
                 
-                other_border[i] = border_width[i] / 3;
+                other_border[j] = border_width[j] / 3;
               }
             
             render_frame_fill (cr, border_box, other_border, colors, dont_draw);