A knife-wielding attacker in France left two primary schoolchildren with only superficial cuts on Thursday but terrified the town of Souffelweyersheim on the outskirts of Strasbourg. Schools in Souffelweyersheim locked down for security reasons after the attack, and a schoolgirl at a nearby secondary school suffered a serious heart attack, according to police. The two schoolgirls cut in the knife attack were taken to the paediatric ward of the university hospital in Strasbourg, while the schoolgirl who suffered a heart attack is being treated in serious condition in hospital. The 28-year-old s…