[pitivi] Fix pylint super-init-not-called

[Thibault Saunier <tsaunier src gnome org>]

commit f2f08106fe93b9c73d272829b2b35440525b10b2
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Sun Oct 27 06:47:24 2019 +0100

    Fix pylint super-init-not-called

 pitivi/dialogs/prefs.py | 2 +-
 pitivi/undo/timeline.py | 6 +-----
 2 files changed, 2 insertions(+), 6 deletions(-)
---
diff --git a/pitivi/dialogs/prefs.py b/pitivi/dialogs/prefs.py
index caa9dc3f..a05532e3 100644
--- a/pitivi/dialogs/prefs.py
+++ b/pitivi/dialogs/prefs.py
@@ -714,7 +714,7 @@ class PluginPreferencesRow(Gtk.ListBoxRow):
     """A row in the plugins list allowing activating and deactivating a plugin."""
 
     def __init__(self, item):
-        Gtk.Bin.__init__(self)
+        Gtk.ListBoxRow.__init__(self)
         self.plugin_info = item.plugin_info
 
         self._container = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL)
diff --git a/pitivi/undo/timeline.py b/pitivi/undo/timeline.py
index ed60d658..5951ab41 100644
--- a/pitivi/undo/timeline.py
+++ b/pitivi/undo/timeline.py
@@ -420,11 +420,7 @@ class TransitionClipAddedAction(TransitionClipAction):
 class TransitionClipRemovedAction(TransitionClipAction):
 
     def __init__(self, ges_layer, ges_clip, track_element):
-        UndoableAction.__init__(self)
-        self.ges_layer = ges_layer
-        self.start = ges_clip.props.start
-        self.duration = ges_clip.props.duration
-        self.track_element = track_element
+        TransitionClipAction.__init__(self, ges_layer, ges_clip, track_element)
 
         self.properties = []
         for property_name in TRANSITION_PROPS: