Allow empty GL_ID
Quick fix, specific to 0.1, for https://gitlab.com/gitlab-org/gitaly/issues/63
Brought up by https://gitlab.com/gitlab-org/gitaly/issues/59
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Quick fix, specific to 0.1, for https://gitlab.com/gitlab-org/gitaly/issues/63
Brought up by https://gitlab.com/gitlab-org/gitaly/issues/59