In this column: Blackie (Eric Clapton), Greeny (Peter Green), Ex-sunburst (Rory Gallagher), 1956 Fender Stratocaster Black, 1959 Gibson Les Paul, 1961 Fender Stratocaster Sunburst, Lazarus (Joe Bonamassa) Of the hundreds of guitars that blues-rock legend Eric Clapton had his favorite was one that he had a hand in designing. In 1970 Eric was at Sho-Bud …