R1:5e6e9fcc5652

When purging drafts after a transaction edit, purge all drafts

Summary: Fixes T13071. See that task for discusison. I think this `<= version` constraint is needless in normal cases (it should match everything in the table anyway), and slightly harmful in bizarre cases where a draft somehow gets a much larger ID than it should have.

Test Plan:
- Gave a draft an unreasonably large ID.
- Pre-patch, observed: submitting comments on the draft's object does not clear the draft.
- Post-patch: submitting…