By John Chalmers and Aleksandar Vasovic BRUSSELS/BELGRADE (Reuters) – The European Union on Monday warned of “escalation and violence” after emergency talks between Kosovo and Serbia failed to resolve their long-running dispute over car licence plates used by the ethnic Serb minority in Kosovo. “After many hours of discussion … the two parties did not agree to a solution today,” EU foreign policy chief Josep Borrell said in a statement to the media. “I think that there is an important responsibility on the sides of both leaders for the failure of the talks today and for any escalation and vi…