Update all existing services to use grpc.Errorf errors
Closes https://gitlab.com/gitlab-org/gitaly/issues/79
Refactor from fmt.Errorf to grpc.Errorf
grpc has an error type which we should be using when returning errors back to the caller.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Closes https://gitlab.com/gitlab-org/gitaly/issues/79
Refactor from fmt.Errorf to grpc.Errorf
grpc has an error type which we should be using when returning errors back to the caller.