[ekiga] Better fix for the penultimate commit (about error dialog box)

[Eugen Dedu <ededu src gnome org>]

commit abfef3e25d6282ac869eeb50143344d0b935b580
Author: Eugen Dedu <Eugen Dedu pu-pm univ-fcomte fr>
Date:   Thu Jul 25 17:36:29 2013 +0200

    Better fix for the penultimate commit (about error dialog box)

 lib/engine/gui/gtk-frontend/main_window.cpp |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/lib/engine/gui/gtk-frontend/main_window.cpp b/lib/engine/gui/gtk-frontend/main_window.cpp
index 3355822..48846c5 100644
--- a/lib/engine/gui/gtk-frontend/main_window.cpp
+++ b/lib/engine/gui/gtk-frontend/main_window.cpp
@@ -636,8 +636,8 @@ static bool on_handle_errors (std::string error,
                                                           GTK_DIALOG_MODAL,
                                                           GTK_MESSAGE_ERROR,
                                                           GTK_BUTTONS_OK,
-                                                          error.c_str (),
-                                                          NULL);
+                                                          "%s",
+                                                          error.c_str ());
 
   gtk_window_set_title (GTK_WINDOW (dialog), _("Error"));
   g_signal_connect_swapped (dialog, "response",