[gnote] Add missing #include

[Aurimas Černius <aurimasc src gnome org>]

commit b39d524bc5f53cc3343e865fedd5f33a3997d77f
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Sat Mar 12 21:08:50 2016 +0200

    Add missing #include
    
    Used to come from notewindow.hpp

 src/synchronization/syncdialog.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/synchronization/syncdialog.cpp b/src/synchronization/syncdialog.cpp
index 9378ae0..ad70fc1 100644
--- a/src/synchronization/syncdialog.cpp
+++ b/src/synchronization/syncdialog.cpp
@@ -1,7 +1,7 @@
 /*
  * gnote
  *
- * Copyright (C) 2012-2014 Aurimas Cernius
+ * Copyright (C) 2012-2014,2016 Aurimas Cernius
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -23,6 +23,7 @@
 #include <boost/bind.hpp>
 #include <boost/format.hpp>
 #include <glibmm/i18n.h>
+#include <gtkmm/radiobutton.h>
 #include <gtkmm/scrolledwindow.h>
 #include <gtkmm/stock.h>
 #include <gtkmm/treeview.h>