[gnome-2048] Disable undo on new game (bgo#759888)

[Robert Roth <robertroth src gnome org>]

commit b6b115673c234daad02683d3641221d307d85402
Author: Robert Roth <robert roth off gmail com>
Date:   Sun Dec 27 00:29:38 2015 +0200

    Disable undo on new game (bgo#759888)

 src/game.vala |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/game.vala b/src/game.vala
index 5073df0..f18e6e3 100644
--- a/src/game.vala
+++ b/src/game.vala
@@ -127,6 +127,7 @@ public class Game : GLib.Object
     score = 0;
     _state = GameState.SHOWING_FIRST_TILE;
     _create_random_tile ();
+    undo_disabled ();
   }
 
   public void undo ()