[pitivi/gtktimeline] render: Cast the GError to string when trying to display it in the dialog

[Thibault Saunier <tsaunier src gnome org>]

commit 97da41387ab77ac68ce10e8de4629a16778b7cd6
Author: Thibault Saunier <tsaunier gnome org>
Date:   Mon Jun 1 13:23:26 2015 +0200

    render: Cast the GError to string when trying to display it in the dialog
    
    Fixes http://phabricator.freedesktop.org/T82

 pitivi/render.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/render.py b/pitivi/render.py
index 6012f6d..bdf4299 100644
--- a/pitivi/render.py
+++ b/pitivi/render.py
@@ -831,7 +831,7 @@ class RenderDialog(Loggable):
         secondary_message = _("An error occured while trying to render your "
                               "project. You might want to check our "
                               "troubleshooting guide or file a bug report. "
-                              "The GStreamer error was:") + "\n\n<i>" + error + "</i>"
+                              "The GStreamer error was:") + "\n\n<i>" + str(error) + "</i>"
 
         dialog = Gtk.MessageDialog(transient_for=self.window, modal=True,
                                    message_type=Gtk.MessageType.ERROR, buttons=Gtk.ButtonsType.OK,