[gtetrinet] Fix build when using -Werror=format-security.

[Jordi Mallach <jordim src gnome org>]

commit 717dc612a884011ec1c0e838db1c9c51b9e533c6
Author: Jordi Mallach <jordi sindominio net>
Date:   Wed Sep 28 14:28:33 2011 +0200

    Fix build when using -Werror=format-security.

 src/tetrinet.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/tetrinet.c b/src/tetrinet.c
index 635c795..ca5c5cf 100644
--- a/src/tetrinet.c
+++ b/src/tetrinet.c
@@ -232,7 +232,7 @@ void tetrinet_inmessage (enum inmsg_type msgtype, char *data)
             dialog = gtk_message_dialog_new (NULL, GTK_DIALOG_MODAL,
                                              GTK_MESSAGE_ERROR,
                                              GTK_BUTTONS_OK,
-                                             buf);
+                                             "%s", buf);
             gtk_dialog_run (GTK_DIALOG(dialog));
             gtk_widget_destroy (dialog);
             g_free (data_utf8);