EmailsOnPushWorker incorrectly claims deleted a commit after a push

This resulted after I pushed: https://gitlab.com/stanhu/gitlab-ce/commit/377b2e44fb875d8d291d25727bdb25520db17035

I saw this in my test emails for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5843, but I thought I'd messed something up with my script.

It looks like we think we have a reverse compare when we shouldn't, but we haven't touched this lately

mentioned in issue #20946 (closed)

Added emails label

Added ~12980 regression labels

Maybe was introduced here: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5401/diffs#diff-22 I remember to talk about with Douwe about the reverse and we think wasn't relevant

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5401#note_13500636

Milestone changed to %8.11

Reassigned to @smcgivern

Started branch 21010-emailsonpushworker-incorrectly-claims-deleted-a-commit-after-a-push

mentioned in merge request !5894 (merged)

Status changed to closed by commit 82a39e3e

mentioned in commit jt-gitlab/gitlab-ce@82a39e3e

mentioned in commit 670dd32a

mentioned in merge request !14785