Users should be able to discard drafts of returned items when the review workflow is on.

[amyehodge]

When the review workflow is on, if an item is returned to the depositor for changes, it is no longer possible to discard the draft item. Neither the collection manager nor the deposit have the power to do this. At this point the revision has not been deposited, so they should be able to discard the draft.

To recreate:

1. go to a collection with the review workflow on
2. create an item and submit it for approval.
3. approve and deposit the item.
4. reopen the same item to make a change (doesn't matter if you make any changes or not)
5. submit it for approval.
6. return to depositor for changes
7. reopen the item to edit. you will not see an option here to discard the item, but you should still be able to do this at this point.