DatabaseOperations(self) TypeError: __init__() takes exactly 1 argument (2 given)

I tried to start a project using this tutorial:
http://www.allbuttonspressed.com/projects/djangoappengine

Got this error when running `./manage.py runserver`:

```$ ./manage.py runserver
Traceback (most recent call last):
  File "./manage.py", line 11, in <module>
    execute_manager(settings)
  File "/home/tony/work/qmag/django-testapp/django/core/management/__init__.py", line 438, in execute_manager
    utility.execute()
  File "/home/tony/work/qmag/django-testapp/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/tony/work/qmag/django-testapp/django/core/management/__init__.py", line 261, in fetch_command
    klass = load_command_class(app_name, subcommand)
  File "/home/tony/work/qmag/django-testapp/django/core/management/__init__.py", line 67, in load_command_class
    module = import_module('%s.management.commands.%s' % (app_name, name))
  File "/home/tony/work/qmag/django-testapp/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/home/tony/work/qmag/django-testapp/djangoappengine/management/commands/runserver.py", line 5, in <module>
    from django.db import connections
  File "/home/tony/work/qmag/django-testapp/django/db/__init__.py", line 78, in <module>
    connection = connections[DEFAULT_DB_ALIAS]
  File "/home/tony/work/qmag/django-testapp/django/db/utils.py", line 94, in __getitem__
    conn = backend.DatabaseWrapper(db, alias)
  File "/home/tony/work/qmag/django-testapp/dbindexer/base.py", line 54, in DatabaseWrapper
    return Wrapper(merged_settings, *args, **kwargs)
  File "/home/tony/work/qmag/django-testapp/dbindexer/base.py", line 37, in __init__
    super(BaseDatabaseWrapper, self).__init__(*args, **kwargs)
  File "/home/tony/work/qmag/django-testapp/djangoappengine/db/base.py", line 290, in __init__
    self.ops = DatabaseOperations(self)
TypeError: __init__() takes exactly 1 argument (2 given)
```

The change in this PR seems to resolve it.