Hold the hallelujahs for this botched Civil War epic about the first black fighting regiment in U.S. history, the Fifty-fourth Massachusetts Volunteer Infantry. Led by white officers, with Colonel Robert Gould Shaw of Boston in command, the Fifty-fourth faced virulent racism but distinguished itself in battle. Until now, Hollywood has never acknowledged the contribution black soldiers made in the Civil War (by war's end, they constituted twelve percent of the Union army). So what went wrong with…