LONDON (Reuters) - Bank of England Governor Mark Carney has dismissed a claim by Boris Johnson, the front-runner in the race to become prime minister, that Britain can avoid the hit of European Union trade tariffs in the event of a no-deal Brexit.Carney told the BBC that leaving the EU without a transition deal should be a choice taken with "absolute clarity" about what it would mean for Britain's economy.The central bank governor said there would be long-term as well as short-term damage for..