By Huw Jones LONDON (Reuters) -The Intercontinental Exchange is considering shifting the clearing of contracts that underpin global debt markets away from London, two industry sources said on Wednesday. A potential relocation to Chicago is being evaluated, the sources said of a move that could stoke fresh concerns about Britain’s post-Brexit role in global finance. Clearing has become a politically sensitive topic since Britain left the European Union, with Brussels saying that UK-based clearing houses such as ICE Clear Europe and the London Stock Exchange’s LCH would no longer be able to serv…