[gtkmm] Menushell: Use noexcept on the destructor implementation.

[Murray Cumming <murrayc src gnome org>]

commit 1bcbf7a61c1bc7e48bd6fdc55e35d4bf4d75c775
Author: Emeric Maschino <emeric maschino gmail com>
Date:   Wed Dec 9 20:20:26 2015 +0100

    Menushell: Use noexcept on the destructor implementation.
    
    To match the generated declaration.
    Bug #759262

 gtk/src/menushell.ccg |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/src/menushell.ccg b/gtk/src/menushell.ccg
index 2e5a988..5706f20 100644
--- a/gtk/src/menushell.ccg
+++ b/gtk/src/menushell.ccg
@@ -43,7 +43,7 @@ MenuShell::MenuShell(GtkMenuShell* castitem)
 {}
 
 // TODO: Why do we need a custom dtor?
-MenuShell::~MenuShell()
+MenuShell::~MenuShell() noexcept
 {}
 
 void MenuShell::accelerate(Window& window)