Remove url.conf.defaults deprecation warns from Django 1.5 upgrade

Change the names of the url.conf imports to be compatible with Django
1.5 syntax.

Resolves https://github.com/openhatch/oh-mainline/issues/1366
Merge pull request #1373 from onceuponatimeforever/1366

Remove url.conf.defaults deprecation warns from Django 1.5 upgrade