Stop MR conflict code from blowing up when branches are missing (9.2)
Port of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11501 for 9-2-stable.
/cc @timothyandrew
Edited by Robert Speicher
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Port of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11501 for 9-2-stable.
/cc @timothyandrew