Do not set closed_at to nil when issue is reopened
back port of one behavior introduced here: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1540/diffs
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
back port of one behavior introduced here: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1540/diffs