Fix DataCard publish and unpublish issues.

Cards were not using their updated ContentProvided authority to
unpublish and publish. Fix these problems. Unpublish was incorrectly
deleting the DataCard before deleting related images, which would fail
as they have a foreign key referencing the DataCard. Delete images
first, then the DataCard.

Change-Id: Id770a87d9badf7f0f35398996f3849104e6a8f8a