[reviewboard] Update to the latest version of django-pipeline.
Review Request #4751 — Created Oct. 15, 2013 and submitted
Update to the latest version of django-pipeline.
Now that django-pipeline has an explicit setting for enabling/disabling
media pipelining, and now that we're using Django 1.5, we can make use
of it again. This upgrades us to the latest release of pipeline.
Tested with a development setup and a production install.
Building packages worked.