Switch binaries over to using python3.

bin/dul-receive-pack

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3 -u
 # dul-receive-pack - git-receive-pack in python
 # Copyright (C) 2008 John Carr <john.carr@unrouted.co.uk>
 #

bin/dul-upload-pack

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3 -u
 # dul-upload-pack - git-upload-pack in python
 # Copyright (C) 2008 John Carr <john.carr@unrouted.co.uk>
 #

bin/dulwich

@@ -1,4 +1,4 @@
-#!/usr/bin/python -u
+#!/usr/bin/python3 -u
 #
 # dulwich - Simple command-line interface to Dulwich
 # Copyright (C) 2008-2011 Jelmer Vernooij <jelmer@jelmer.uk>