[gitg] window: fix warning when unbinding property

[Ignacio Casal Quinteiro <icq src gnome org>]

commit 43c16c837abc4e2f64693953a0f97074e25f5d45
Author: Ignacio Casal Quinteiro <icq gnome org>
Date:   Fri Nov 14 16:03:43 2014 +0100

    window: fix warning when unbinding property
    
    https://bugzilla.gnome.org/show_bug.cgi?id=740117

 gitg/gitg-window.vala |    6 +-----
 1 files changed, 1 insertions(+), 5 deletions(-)
---
diff --git a/gitg/gitg-window.vala b/gitg/gitg-window.vala
index 6e16f54..026407a 100644
--- a/gitg/gitg-window.vala
+++ b/gitg/gitg-window.vala
@@ -539,11 +539,7 @@ public class Window : Gtk.ApplicationWindow, GitgExt.Application, Initable
                var selectable = (current as GitgExt.Selectable);
                d_select_button.visible = (selectable != null);
 
-               if (d_selectable_mode_binding != null)
-               {
-                       d_selectable_mode_binding.unbind();
-                       d_selectable_mode_binding = null;
-               }
+               d_selectable_mode_binding = null;
 
                if (selectable != null)
                {