Unavailable on home video for many years (except perhaps as a grainy, nth-generation VHS bootleg), Penelope Spheeris’ seminal document of the young 1979-1980 Los Angeles punk scene includes chaotic live performances by now-legendary groups like Black Flag (with short-lived lead singer Ron “Chavo Pederast” Reyes), X (giving themselves stick-and-poke tattoos) and the Germs (whose…