[pitivi] gst: import gst modules to have GTypes loaded. Fixes #583595

[Edward Hervey <edwardrv src gnome org>]

commit 6550234a2a6cebb2aa2a793c054ad444fd1ecbca
Author: Edward Hervey <bilboed bilboed com>
Date:   Sat May 23 18:08:56 2009 +0200

    gst: import gst modules to have GTypes loaded. Fixes #583595
    
    This is so we can load caps that have GstAudioChannelPosition for
    example.
---
 pitivi/pitivigstutils.py |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/pitivi/pitivigstutils.py b/pitivi/pitivigstutils.py
index c64fcc2..a15c144 100644
--- a/pitivi/pitivigstutils.py
+++ b/pitivi/pitivigstutils.py
@@ -26,6 +26,9 @@ that we don't have to depend on too recent versions of gst-python.
 """
 
 import gst
+import gst.interfaces
+import gst.audio
+import gst.video
 
 def fraction_float(frac):
     """ override for gst.Fraction.__float__ """