Summary:
Ref T13253. Fixes T6615. See that task for discussion.
- Remove three keys which serve no real purpose: `dataID` doesn't do anything for us, and the two `leaseOwner` keys are unused.
- Rename `leaseOwner_2` to `key_owner`.
- Fix an issue where `dataID` was nullable in the active table and non-nullable in the archive table.
In practice, //all// workers have data, so all workers have a `dataID`: if they didn't, we'd already fatal when trying to move tasks to the archive table. Just clean this up for consistency, and remove the ancient codepath which imagined tasks with no data.
Test Plan:
- Ran `bin/storage upgrade`, inspected tables.
- Ran `bin/phd debug taskmaster`, worked through a bunch of tasks with no problems.
Reviewers: amckinley
Reviewed By: amckinley
Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam
Maniphest Tasks: T13253, T6615
Differential Revision: https://secure.phabricator.com/D20175
