This is a repeat, but a very valuable and welcome one, presenting an encore of the Great Performances telecast of the 1992 Madison Square Garden concert saluting Bob Dylan’s 30 years as a recording artist. He’s still going more than 20 years later, but some of the other concert performers are not: George Harrison and Richie Havens, just to name two. But my, what a lineup, and what performances: Tom Petty, Eric Clapton, The Band, Eddie Vedder, Neil Young, Stevie Wonder, Roger Mc