I know the question has been answered already but …
A Much simpler approach is to dump the auth module data into a json file once the superuser has been created:
./manage.py dumpdata --indent=2 auth > initial_data.json
You can also dump the sessions data:
./manage.py dumpdata --indent=2 sessions
You can then append the session info to the auth module dump (and probably increase the expire_date so it does not expire… ever ;-).
From then, you can use
/manage.py syncdb --noinput
to load the superuser and his session when creating the db with no interactive prompt asking you about a superuser.