[pitivi] Fix setting transition types

[Thibault Saunier <tsaunier src gnome org>]

commit c46cf799da0084f4a305bb1f0a2b1acfb51920b2
Author: Thibault Saunier <tsaunier gnome org>
Date:   Mon Jun 1 10:29:13 2015 +0200

    Fix setting transition types
    
    Fixes http://phabricator.freedesktop.org/T78

 pitivi/transitions.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/transitions.py b/pitivi/transitions.py
index eb5a39a..91a5c1a 100644
--- a/pitivi/transitions.py
+++ b/pitivi/transitions.py
@@ -173,7 +173,7 @@ class TransitionsListWidget(Gtk.Box, Loggable):
         else:
             self.props_widgets.set_sensitive(True)
 
-        self.element.set_asset(transition_asset)
+        self.element.get_parent().set_asset(transition_asset)
         self.app.write_action("element-set-asset", {
             "asset-id": transition_asset.get_id(),
             "element-name": self.element.get_name()})