[gtkmm-documentation] PlacesSidebar example: Fix with gtkmm from master.

[Murray Cumming <murrayc src gnome org>]

commit e4c72b64789b1cab0a313da9caf1d7bb01140997
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Sep 23 14:15:23 2013 +0200

    PlacesSidebar example: Fix with gtkmm from master.

 examples/book/placessidebar/examplewindow.cc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/examples/book/placessidebar/examplewindow.cc b/examples/book/placessidebar/examplewindow.cc
index fe9066b..a540243 100644
--- a/examples/book/placessidebar/examplewindow.cc
+++ b/examples/book/placessidebar/examplewindow.cc
@@ -40,7 +40,7 @@ ExampleWindow::ExampleWindow()
 
   m_places_sidebar.signal_open_location().connect(sigc::mem_fun(*this, 
&ExampleWindow::on_placessidebar_open_location));
   m_places_sidebar.signal_populate_popup().connect(sigc::mem_fun(*this, 
&ExampleWindow::on_placessidebar_populate_popup));
-  m_places_sidebar.signal_drag_action_requested().connect(sigc::mem_fun(*this, 
&ExampleWindow::on_placessidebar_drag_action_requested));
+  //m_places_sidebar.signal_drag_action_requested().connect(sigc::mem_fun(*this, 
&ExampleWindow::on_placessidebar_drag_action_requested));
 
   m_controls.attach(m_show_desktop_check, 0, 0, 1, 1);
   m_controls.attach(m_show_connect_to_server_check, 0, 1, 1, 1);