A nightclub manager who pleaded guilty to manslaughter in the beating death of jazz bassist Jaco Pastorius was sentenced to 21 months in prison and placed on five years' probation. Broward County Circuit Judge M. Daniel Futch Jr. agreed to the maximum sentence possible for Luc Havan. Pastorius, 35, of Fort Lauderdale, died Sept. 21, 1987, of severe head injuries received in a beating 10 days earlier by Havan, 26, of Oakland Park, police said. Investigators said Pastorius was drunk and tried to gain entrance to the after-hours club Havan managed. In his plea, Havan contended he pushed Pastorius as he tried to enter the club. Pastorius, a three-time Grammy Award nominee, was hailed for his innovative work on the bass guitar. He worked with such performers as Weather Report, Joni Mitchell, Herbie Hancock and Blood, Sweat and Tears.