Plot: Touted as one of the most influential and successful American rock groups of the 1970s, The Allman Brothers Band recently regrouped and turned out their first new album in nine years: Seven Turns. In this special edition of ""MTV Unplugged,"" original band members Gregg Allman on keyboards, Dickey Betts on guitar, and drummers Butch Truck and Jaimoe, are joined by new members, guitarist Warren Haynes, bassist Allen Woody, and Johnny Neel on keyboards and blues harp