Summary:
Ref T5833. This fixes a few weird things with this table:
- A bunch of columns were nullable for no reason.
- We stored an MD5 hash of the key (unusual) but never used it and callers were responsible for manually populating it.
- We didn't perform known-key-text lookups by using an index.
Test Plan:
- Ran migrations.
- Faked duplicate keys, saw them clean up correctly.
- Added new keys.
- Generated new keys.
- Used `bin/auth-ssh` and `bin/auth-ssh-key`.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T5833
Differential Revision: https://secure.phabricator.com/D10805
