[gnome-mines] Fix window size growing huge with GTK+ 3.20

[Michael Catanzaro <mcatanzaro src gnome org>]

commit e69542a603b47f773e8305dbe7a20d2e42fe7eaa
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Sun Feb 14 20:56:57 2016 -0600

    Fix window size growing huge with GTK+ 3.20

 src/gnome-mines.vala |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/src/gnome-mines.vala b/src/gnome-mines.vala
index 886bbb4..e8287e4 100644
--- a/src/gnome-mines.vala
+++ b/src/gnome-mines.vala
@@ -402,8 +402,7 @@ public class Mines : Gtk.Application
     {
         if (!is_maximized && !is_tiled && !window_skip_configure)
         {
-            window_width = allocation.width;
-            window_height = allocation.height;
+            window.get_size (out window_width, out window_height);
         }
 
         window_skip_configure = false;