R1:5529458e14eb

Add test coverage for SSH key revocation

Summary: Depends on D18928. Ref T13043. Add some automated test coverage for SSH revocation rules.

Test Plan: Ran tests, got a clean bill of health.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13043

Differential Revision: https://secure.phabricator.com/D18929