[ekiga] Fix compile error with -Wformat-security

[Eugen Dedu <ededu src gnome org>]

commit 75383ece9b4fc72a99edf79773d00f0538f454a5
Author: Eugen Dedu <Eugen Dedu pu-pm univ-fcomte fr>
Date:   Fri Sep 28 09:55:47 2012 +0200

    Fix compile error with -Wformat-security
    
    This flag is automatically used by debian for ex.

 lib/engine/gui/gtk-frontend/call-window.cpp |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/lib/engine/gui/gtk-frontend/call-window.cpp b/lib/engine/gui/gtk-frontend/call-window.cpp
index 8631ec8..79d26e9 100644
--- a/lib/engine/gui/gtk-frontend/call-window.cpp
+++ b/lib/engine/gui/gtk-frontend/call-window.cpp
@@ -1588,7 +1588,10 @@ ekiga_call_window_set_bandwidth (EkigaCallWindow *cw,
     msg = g_strdup_printf (_("A:%.1f/%.1f V:%.1f/%.1f FPS:%d/%d"),
                            ta, ra, tv, rv, tfps, rfps);
 
-  gm_statusbar_push_message (GM_STATUSBAR (cw->priv->statusbar), msg);
+  if (msg)
+    gm_statusbar_push_message (GM_STATUSBAR (cw->priv->statusbar), "%s", msg);
+  else
+    gm_statusbar_push_message (GM_STATUSBAR (cw->priv->statusbar), NULL);
   g_free (msg);
 }