[gnome-tweak-tool] extensions: Bail out early when not running under GNOME

[Florian Müllner <fmuellner src gnome org>]

commit 1e9b9efb6a54bac3e3bcb5300a89f725fec718a6
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Jun 8 20:24:35 2017 +0200

    extensions: Bail out early when not running under GNOME
    
    GNOME Shell extensions aren't useful in non-GNOME environments,
    so return right after initializing the empty tweak group to make
    sure it is kept hidden in that case.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=783563

 gtweak/tweaks/tweak_group_shell_extensions.py |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/gtweak/tweaks/tweak_group_shell_extensions.py b/gtweak/tweaks/tweak_group_shell_extensions.py
index 266dfce..b0ed587 100644
--- a/gtweak/tweaks/tweak_group_shell_extensions.py
+++ b/gtweak/tweaks/tweak_group_shell_extensions.py
@@ -237,12 +237,14 @@ class ShellExtensionTweakGroup(ListBoxTweakGroup):
                                    _("Extensions"),
                                    *extension_tweaks)
 
+        if shell is None:
+            return # we're done
+
         self.props.valign = Gtk.Align.FILL
 
         self.titlebar_widget = Gtk.Switch(visible=True)
-        if shell is not None:
-            shell._settings.bind("disable-user-extensions", self.titlebar_widget,
-                                 "active", Gio.SettingsBindFlags.INVERT_BOOLEAN)
+        shell._settings.bind("disable-user-extensions", self.titlebar_widget,
+                             "active", Gio.SettingsBindFlags.INVERT_BOOLEAN)
 
         self.set_header_func(self._list_header_func, None)
         self.connect("row-activated", self._on_row_activated, None);