By Meg Shen and James Pomfret HONG KONG (Reuters) -There is no reason to change Hong Kong’s “one country, two systems” formula of governance, Chinese President Xi Jinping said on a rare visit to the global financial hub after swearing in the city’s new leader, John Lee, on Friday. Britain returned Hong Kong to Chinese rule on July 1, 1997, with Beijing promising wide-ranging autonomy, unfettered individual rights and judicial independence at least until 2047. China’s critics accuse authorities of trampling on those freedoms, unavailable on the authoritarian mainland, with a sweeping national s…