[gnome-shell] st-icon: check if gicon is null before unref.

[Adel Gadllah <agadllah src gnome org>]

commit e96d9e0ea1bb4043012890b0cdb69fbf2b7bc911
Author: Alban Browaeys <prahal yahoo com>
Date:   Thu Apr 25 18:25:12 2013 +0200

    st-icon: check if gicon is null before unref.
    
    Commit a6b49fe7d6c9bcd8a2be47a0b0b44cf9a53a45aa
    introduced a check for equality of priv->gicon vs gicon
    and unref then return early if so. But if both are null,
    we should not unref gicon. Only return.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=698863

 src/st/st-icon.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/st/st-icon.c b/src/st/st-icon.c
index b29744b..3fec7e2 100644
--- a/src/st/st-icon.c
+++ b/src/st/st-icon.c
@@ -544,7 +544,8 @@ st_icon_set_icon_name (StIcon      *icon,
 
   if (g_icon_equal (priv->gicon, gicon)) /* do nothing */
     {
-      g_object_unref (gicon);
+      if (gicon)
+        g_object_unref (gicon);
       return;
     }