Jan 28 (Reuters) - A South Carolina judge on Wednesday vacated the 54-year-old trespassing convictions of a group of black civil rights protesters credited with reinvigorating the 1960s U.S. sit-in movement against segregated lunch counters. The "Friendship Nine," a group of mostly students at the now-closed Friendship College, agreed to risk arrest by sitting at the McCrory's five-and-dime store lunch counter in Rock Hill on Jan.