[gnome-dictionary] Silence a compiler warning

[Emmanuele Bassi <ebassi src gnome org>]

commit c1f68c26794ada47c55eb70cc6f0f341199c73ae
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Apr 11 12:01:32 2017 +0100

    Silence a compiler warning
    
    We don't use the message variable.
    
    We should remove it entirely, now that we don't have a status bar any
    more, but this is the path of least resistance.

 src/gdict-window.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gdict-window.c b/src/gdict-window.c
index 97f2a2f..d61b91a 100644
--- a/src/gdict-window.c
+++ b/src/gdict-window.c
@@ -1196,7 +1196,7 @@ sidebar_page_changed_cb (GdictSidebar *sidebar,
                         GdictWindow  *window)
 {
   const gchar *page_id;
-  const gchar *message;
+  const gchar *message G_GNUC_UNUSED;
 
   page_id = gdict_sidebar_current_page (sidebar);