Do we need to install django-kombu? But shouldn't this be a dependenc…

…y of django-celery? My head hurts.

.travis.yml

@@ -16,7 +16,7 @@ install:
  # Required library dependencies
  - pip install boto six
  # Optional library dependencies
- - pip install celery django-celery
+ - pip install celery django-celery django-kombu
  # The version of Django being tested against
  - pip install -q Django==$DJANGO_VERSION