dmwm/DAS — pull request #4083 by vidma (2013-12-05 15:08:50+00:00)
Title: fix clean_worker to respect expiration timestamps

* spec must be passed as a positional arg to collection.remove
* otherwise, passing a kwarg removes EVERYTHING from the collection, i.e. each time cleanup_worker was run, it would wipe whole collection!

fixes issue #4082