ALBANY (AP).- The Union’s first black hero of the Civil War wasn’t one of the African-American soldiers of the 54th Massachusetts Infantry Regiment, famously depicted in the 1989 film “Glory,” but rather a merchant ship’s cook who took up arms to prevent being sold into slavery after a Confederate raider captured his vessel. At least that’s the reckoning of some historians and a pair of upstate New York-based documentary producers who have included William Tillman’s story in their new film on the short-but-prolific wartime record of the brig Jefferson Davis, a Southern privateer that seized several Union ships in the opening months of the war. “He certainly ranks among the top half-dozen African-American heroes of the Civil War as far as I’m concerned,” said Gerald