Pick a released security fix into master
Picks https://dev.gitlab.org/gitlab/gitlab-ee/merge_requests/539 (without the changelog entry) into master since it's been released in 9.5.4.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Picks https://dev.gitlab.org/gitlab/gitlab-ee/merge_requests/539 (without the changelog entry) into master since it's been released in 9.5.4.