American basketball star Brittney Griner was headed back to the United States on Friday after being released from a Russian prison in exchange for an arms dealer known as the “Merchant of Death.” Griner, 32, who was arrested in Russia in February on drug charges, and Viktor Bout, 55, who was serving a 25-year sentence in a U.S. prison, were exchanged at an airport in Abu Dhabi. In footage released by Russian state media, Griner, shorn of her distinctive dreadlocks, and a relaxed and animated Bout could be seen crossing paths on the airport tarmac and heading towards the planes that would take …