Generic wrapper for ``django-admin.py``.

def _manage(target, extra='', proj_settings=PROJ_SETTINGS):
    """Generic wrapper for ``django-admin.py``."""
    local("export PYTHONPATH='' && "
          "export DJANGO_SETTINGS_MODULE='%s' && "
          "django-admin.py %s %s" %
          (proj_settings, target, extra),
          capture=False)