[pitivi] Make sure autogen uses python2

[Mathieu Duponchelle <mathieudu src gnome org>]

commit 907a5550e0c3d8591d718d2cc0448fb010450e89
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Thu Jan 9 13:58:58 2014 +0100

    Make sure autogen uses python2

 autogen.sh |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 8ab638f..d5246c0 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+export PYTHON=python2
+
 DIE=0
 package=pitivi
 srcfile=pitivi/application.py