[gnome-software] css: simplify review valutation buttons separator

[Lapo Calamandrei <lapo src gnome org>]

commit 3f3e62ded238d0e23e1f8a8e9a482b2dc509b345
Author: Lapo Calamandrei <calamandrei gmail com>
Date:   Thu Jun 30 17:55:00 2016 +0200

    css: simplify review valutation buttons separator
    
    since the linear gradient with calc() inside makes gnome-software
    crash with gtk+ 3.18.

 src/gtk-style.css |   12 ++----------
 1 files changed, 2 insertions(+), 10 deletions(-)
---
diff --git a/src/gtk-style.css b/src/gtk-style.css
index aa0d796..72d1f79 100644
--- a/src/gtk-style.css
+++ b/src/gtk-style.css
@@ -196,18 +196,10 @@
 
 /* this is the separator between yes and no vote buttons */
 .review-row .vote-buttons button:not(:first-child):not(:hover):not(:active):not(:backdrop) {
-       border-image: linear-gradient(to bottom,
-                                     transparent 5px,
-                                     @borders 5px,
-                                     @borders calc(100% -5px),
-                                     transparent calc(100% -5px)) 0 0 0 1 stretch;
+       border-image: image(@borders) 0 0 0 1 / 5px 0 5px 1px;
 }
   .review-row .vote-buttons button:not(:first-child):backdrop {
-       border-image-source: linear-gradient(to bottom,
-                                             transparent 5px,
-                                             @unfocused_borders 5px,
-                                             @unfocused_borders calc(100% -5px),
-                                             transparent calc(100% -5px));
+       border-image: image(@unfocused_borders) 0 0 0 1 / 5px 0 5px 1px;
   }
 
 .reviewbar {