Use python2 shebang

Some distributions have switched to python3 as default and our code
breaks because it's python2 specific. Follow the PEP 394
recommendation.

bin/sugar-activity

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 
 # Copyright (C) 2006-2008, Red Hat, Inc.
 #

configure.ac

@@ -15,6 +15,7 @@ GNOME_COMPILE_WARNINGS(maximum)
 
 AC_PATH_PROG([GLIB_GENMARSHAL], [glib-genmarshal])
 
+PYTHON=python2
 AM_PATH_PYTHON
 AM_CHECK_PYTHON_HEADERS(,[AC_MSG_ERROR(could not find Python headers)])
 

tests/data/sample.activity/setup.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 
 from sugar3.activity import bundlebuilder
 

tests/test_mime.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 
 # Copyright (C) 2006, Red Hat, Inc.
 # Copyright (C) 2007, One Laptop Per Child