Anti‐thymocyte globulin for graft‐versus‐host disease prophylaxis in patients with intermediate‐ or high‐risk acute myeloid leukaemia undergoing reduced‐intensity conditioning allogeneic stem cell transplantation in first complete remission – a survey on behalf of the Acute Leukaemia Working Party of the European Society for Blood and Marrow Transplantation. (21st February 2018)