R1:ebde9357c7f8

Fix reverting commit language

Summary: I think the language here is inverted? On a commit which is reverted, the text states `$author added a reverted commit: $commit`. In reality, `$commit` is the //reverting// commit, not the //reverted// commit.

Test Plan: Think about English.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D13067