HAVANA( Reuters)-Cuban tourism operators breathed a sigh of relief this week as the first tourists in months returned to sip mojitos and snap selfies in vintage cars in the capital Havana, providing a much-needed shot in the arm to the Caribbean island's ailing economy. Communist-run Cuba has vaccinated nearly its entire population with home-grown inoculations, prompting authorities last week to re-open the country's borders to tourism after a nearly two-year hiatus during the coronavirus pandem