Los Angeles, CA - Hold on to your ripped jeans and flannel, folks, because renowned music producer Butch Vig just dropped a grunge-busting bombshell that's guaranteed to shatter your '90s nostalgia glasses. In a recent interview with Vanflip, Vig, the mastermind behind Nirvana's iconic "Nevermind" album, revealed the band's surprising muse, and it's not who…