Return a HttpResponse in seed_db
Also moved the adding of the django patterns to where they belong so
that they do not get added multiple times.
Patch by: Sverre Rabbelier
# Directions for web crawlers.
# See http://www.robotstxt.org/wc/norobots.html.
User-agent: HTTrack
User-agent: puf
User-agent: MSIECrawler
User-agent: Nutch
Disallow: /