Pulp

ContentUnassociation doesn't really need to be a separate stage, and making it one breaks the expectations of the "pipeline" by changing the semantics of what goes into and out of the queues.

The ContentAssociation stage puts querysets into the queue (instead of declarative content) for the sake of the ContentUnassociation stage, and also these querysets represent content to remove rather than content to add.

Furthermore this isn't necessary. Rather than toggling whether the ContentUnassociation stage is run as a whole, we can just pass a boolean parameter into the ContentAssociation stage to toggle the behavior.