[iagno] Don't allow undo after the game is over

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 0b3ccf9f6a861b264431aaaf09b2af341365b89a
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sun Sep 15 19:00:24 2013 -0500

    Don't allow undo after the game is over
    
    This doesn't work as expected if the board has been flipped.

 src/iagno.vala |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/iagno.vala b/src/iagno.vala
index 86aedeb..169a95e 100644
--- a/src/iagno.vala
+++ b/src/iagno.vala
@@ -375,6 +375,8 @@ public class Iagno : Gtk.Application
     private void game_complete_cb ()
     {
         update_ui ();
+        undo_action.set_enabled (false);
+
         if (game.n_light_tiles > game.n_dark_tiles)
             show_message (_("Light player wins!"), Gtk.MessageType.INFO);
         if (game.n_dark_tiles > game.n_light_tiles)