fix(tests): fix deprecated imports for Django <1.6
fix(tests): fix deprecated imports for Django <1.6

This fixes an import that breaks in older versions of Django. It's just
the 'django.conf.urls.defaults' import that was deprecated and removed
in Django 1.6.

Amanit/django-celery,digimarc/django-celery,kanemra/django-celery,kanemra/django-celery,georgewhewell/django-celery,tkanemoto/django-celery,celery/django-celery,tkanemoto/django-celery,Amanit/django-celery,axiom-data-science/django-celery,tkanemoto/django-celery,axiom-data-science/django-celery,CloudNcodeInc/django-celery,georgewhewell/django-celery,celery/django-celery,iris-edu-int/django-celery,iris-edu-int/django-celery,iris-edu-int/django-celery,digimarc/django-celery,georgewhewell/django-celery,CloudNcodeInc/django-celery,CloudNcodeInc/django-celery,celery/django-celery,Amanit/django-celery,kanemra/django-celery,digimarc/django-celery,axiom-data-science/django-celery