MONTREUX, Switzerland, July 6: American singer-songwriter Sixto “Sugar Man” Rodriguez, virtually unknown a few years ago, opened the Montreux Jazz Festival on Thursday, which American producer and its former co-director Quincy Jones calls the “Rolls Royce of music festivals.” Fresh from the Glastonbury festival in Britain last weekend, Rodriguez gave a Fourth of July concert in the Swiss resort, mixing songs from his two albums that never made the charts with borrowed tunes including the classic rock’n’roll hit “Fever.” (agencies)