Update the mirror delay to something that's valid in controller spec
Extracted from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2431 to address a failure currently in EE master -- https://gitlab.com/gitlab-org/gitlab-ee/issues/3008
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Extracted from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2431 to address a failure currently in EE master -- https://gitlab.com/gitlab-org/gitlab-ee/issues/3008