[gnome-calendar] css: `-gtk-icon-shadow` in place of `icon-shadow`

[Lapo Calamandrei <lapo src gnome org>]

commit 318c200d6f23566e07f2685454dba6ca0c696fb8
Author: Lapo Calamandrei <calamandrei gmail com>
Date:   Fri Jul 8 01:59:28 2016 +0200

    css: `-gtk-icon-shadow` in place of `icon-shadow`
    
    muscle memory fail.

 data/theme/gtk-styles.css |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/data/theme/gtk-styles.css b/data/theme/gtk-styles.css
index 9d32b06..2e403ca 100644
--- a/data/theme/gtk-styles.css
+++ b/data/theme/gtk-styles.css
@@ -291,9 +291,9 @@ event-widget.color-light:backdrop {
 .sources-button:hover:not(:backdrop) {
     background-image: none;
     text-shadow: none;
-    icon-shadow: 0 1px alpha(black, 0.1);
+    -gtk-icon-shadow: 0 1px alpha(black, 0.1);
 }
 
 .sources-button:not(:backdrop) {
-    icon-shadow: 0 1px alpha(black, 0.1);
+    -gtk-icon-shadow: 0 1px alpha(black, 0.1);
 }