[gnome-tweak-tool] widgets: Replace long-deprecated Gtk.HBox

[Jeremy Bicha <jbicha src gnome org>]

commit 7954e1b7e1f5819f01d947fba8ed5c32913eed7c
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Sun Jun 11 13:25:06 2017 -0400

    widgets: Replace long-deprecated Gtk.HBox

 gtweak/widgets.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtweak/widgets.py b/gtweak/widgets.py
index 5a46fac..a94009f 100644
--- a/gtweak/widgets.py
+++ b/gtweak/widgets.py
@@ -53,7 +53,7 @@ def build_label_beside_widget(txt, *widget, **kwargs):
     if kwargs.get("hbox"):
         hbox = kwargs.get("hbox")
     else:
-        hbox = Gtk.HBox()
+        hbox = Gtk.Box()
 
     hbox.props.spacing = UI_BOX_SPACING
     lbl = Gtk.Label(label=txt)