[gparted] Stop including removed <sigc++/class_slot.h> header (#756035)

[Curtis Gedak <gedakc src gnome org>]

commit d925bd2bb592160bd9b760c200fbeb7c9d24b2a1
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Sun Oct 4 10:57:59 2015 +0100

    Stop including removed <sigc++/class_slot.h> header (#756035)
    
    Libsigc++2 version 2.5.2 and later removed header file
    <sigc++/class_slot.h>.  Quoting the NEWS file for version 2.5.2:
    
        Remove useless headers: sigc++/class_slot.h ...
    
    Libsigc++2 version 2.5.2 NEWS file:
    https://git.gnome.org/browse/libsigc++2/tree/NEWS?id=2.5.2
    
    Bug 756035 - GParted does not compile with newer gtkmm libraries in
                 Fedora 23

 include/Win_GParted.h |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/include/Win_GParted.h b/include/Win_GParted.h
index 148a2c8..57c7ce4 100644
--- a/include/Win_GParted.h
+++ b/include/Win_GParted.h
@@ -25,7 +25,6 @@
 #include "../include/GParted_Core.h"
 #include "../include/HBoxOperations.h" 
 
-#include <sigc++/class_slot.h>
 #include <gtkmm/paned.h>
 #include <gtkmm/toolbar.h>
 #include <gtkmm/separatortoolitem.h>