In the tradition of its femmes-behind-bars forerunners, this remake of the Warner Bros. genre landmark Caged is reform-minded in its story and spiked with provocatively pitched elements (including a doozy of a catfight riot). "Secrets of the Cells! Innocents Thrown in with Female Bully-Boys!" shouted movie ads. Erica (Shirley Knight) is one of the innocents, pregnant and unjustly locked up for a five-year stint. She gives birth, her chi