[gnote] Make method const

[Aurimas Černius <aurimasc src gnome org>]

commit 1c18b6fc11ade77ce47e1e116407c3c77bd5ca4c
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Sun Dec 27 14:57:53 2015 +0200

    Make method const

 src/addininfo.hpp |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/addininfo.hpp b/src/addininfo.hpp
index 40e1342..fa346db 100644
--- a/src/addininfo.hpp
+++ b/src/addininfo.hpp
@@ -1,7 +1,7 @@
 /*
  * gnote
  *
- * Copyright (C) 2013-2014 Aurimas Cernius
+ * Copyright (C) 2013-2015 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
@@ -84,7 +84,7 @@ public:
     {
       m_addin_module = module;
     }
-  const std::map<Glib::ustring, Glib::ustring> & attributes()
+  const std::map<Glib::ustring, Glib::ustring> & attributes() const
     {
       return m_attributes;
     }