Comment 2 for bug 1049570

This problem is due to the old version of django, e.g version 1.3 on Ubuntu 11.04. This can be resolved by upgrade django to 1.4+. use following command to upgrade and verify.
sudo apt-get remove --purge python-django
sudo pip install --upgrade django
django-admin --version

Here's a link of how to-do.
http://stackoverflow.com/questions/10564757/turnkey-django-how-to-upgrade-django-to-1-4

My suggestion is the install script in devstack need to check the django version to upgrade if necessary.