By Fabian Bimmer BROKSTEDT, Germany (Reuters) -Two people were killed and several others injured when a 33-year-old stateless Palestinian man attacked them with a knife on Wednesday on a regional train travelling between Kiel and Hamburg in northern Germany, authorities said. Police in the state of Schlewsig-Holstein on the Danish border said the man, who was himself lightly injured, was being treated in hospital. He was arrested at a train stop in the village of Brokstedt. Three others were seriously injured in the attack and four were lightly injured, authorities said. There was no informati…