[gparted] Use Gtk::Box for HBoxOperations (!25)

[Mike Fleetwood <mfleetwo src gnome org>]

commit b0f455c70210ea1be47ccbc277786664f830deb8
Author: Luca Bacci <luca bacci982 gmail com>
Date:   Wed Feb 27 16:15:56 2019 +0100

    Use Gtk::Box for HBoxOperations (!25)
    
    Gtk::HBox and Gtk::VBox were deprecated in Gtkmm 3.2.  Replace with
    plain Gtk::Box.
    
    This commit makes the change for HBoxOperations.{h,cc}.
    
    Closes !25 - Modern Gtk3 - part 1

 include/HBoxOperations.h | 2 +-
 src/HBoxOperations.cc    | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/include/HBoxOperations.h b/include/HBoxOperations.h
index 2511fd5f..fdc2a767 100644
--- a/include/HBoxOperations.h
+++ b/include/HBoxOperations.h
@@ -28,7 +28,7 @@
 namespace GParted
 {
 
-class HBoxOperations : public Gtk::HBox
+class HBoxOperations : public Gtk::Box
 {
 public:
        HBoxOperations() ;
diff --git a/src/HBoxOperations.cc b/src/HBoxOperations.cc
index a420756b..09bce99e 100644
--- a/src/HBoxOperations.cc
+++ b/src/HBoxOperations.cc
@@ -23,7 +23,8 @@
 namespace GParted
 {
 
-HBoxOperations::HBoxOperations() 
+HBoxOperations::HBoxOperations()
+ : Gtk::Box(Gtk::ORIENTATION_HORIZONTAL)
 {
        //create listview for pending operations
        liststore_operations = Gtk::ListStore::create( treeview_operations_columns );