[gnome-tweak-tool] appearance: Stop requiring gtk2 version of theme

[Jeremy Bicha <jbicha src gnome org>]

commit b7ed82743030600e199f287b88f96ce015ab2b05
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Fri Nov 3 14:30:30 2017 -0400

    appearance: Stop requiring gtk2 version of theme

 gtweak/tweaks/tweak_group_appearance.py |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)
---
diff --git a/gtweak/tweaks/tweak_group_appearance.py b/gtweak/tweaks/tweak_group_appearance.py
index 7380c47..be79891 100644
--- a/gtweak/tweaks/tweak_group_appearance.py
+++ b/gtweak/tweaks/tweak_group_appearance.py
@@ -45,7 +45,7 @@ class GtkThemeSwitcher(GSettingsComboTweak):
             **options)
 
     def _get_valid_themes(self):
-        """ Only shows themes that have variations for gtk+-3 and gtk+-2 """
+        """ Only shows themes that have variations for gtk3"""
         gtk_ver = Gtk.MINOR_VERSION
         if gtk_ver % 2: # Want even number
             gtk_ver += 1
@@ -54,9 +54,8 @@ class GtkThemeSwitcher(GSettingsComboTweak):
                  os.path.join(GLib.get_user_data_dir(), "themes"),
                  os.path.join(os.path.expanduser("~"), ".themes"))
         valid = walk_directories(dirs, lambda d:
-                    os.path.exists(os.path.join(d, "gtk-2.0")) and \
-                        (os.path.exists(os.path.join(d, "gtk-3.0")) or \
-                         os.path.exists(os.path.join(d, "gtk-3.{}".format(gtk_ver)))))
+                    os.path.exists(os.path.join(d, "gtk-3.0", "gtk.css")) or \
+                         os.path.exists(os.path.join(d, "gtk-3.{}".format(gtk_ver))))
 
         if 'Adwaita' not in valid:
             valid += ['Adwaita']