[brasero] If we fail to build a proper pipeline make sure we properly set it to NULL in the Private structure

[Philippe Rouquier <philippr src gnome org>]

commit 6b99ea66f23a271327d8e96212cd239247c45a8a
Author: Philippe Rouquier <bonfire-app wanadoo fr>
Date:   Sun Dec 6 13:14:05 2009 +0100

    If we fail to build a proper pipeline make sure we properly set it to NULL in the Private structure
    Kills some warnings
    It should be backported to 2.28

 plugins/transcode/burn-vob.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/plugins/transcode/burn-vob.c b/plugins/transcode/burn-vob.c
index 81a6b9b..a5ad6a2 100644
--- a/plugins/transcode/burn-vob.c
+++ b/plugins/transcode/burn-vob.c
@@ -1153,6 +1153,7 @@ error:
 				 (*error)->message);
 
 	gst_object_unref (GST_OBJECT (pipeline));
+	priv->pipeline = NULL;
 	return FALSE;
 }