The real deal Linda Ronstadt's current tour – 'a history lesson of music' – reflects her dedication to authenticity, and quality By George Varga July 15, 2004 Other singers may have a greater passion for music than Linda Ronstadt. But few have a greater passion for more types of music, or the willingness to perform them, even at the risk of falling on her face. "My career has befuddled other people, and it's befuddled me," admitted Ronstadt, 58, who finds her fans are polarized by her nightly on-stage salute to "Fahrenheit 9/11" filmmaker Michael Moore. "I've been dedicating a song...