The problem with "The Runaways," a street-level snapshot of the creation of the groundbreaking '70s all-girl rock band, is that they went with the wrong girl. Instead of training the lens on the Runaways' artistic rebel who hung around and became legend, rocker Joan Jett, played with serious punk grrl power by Kristen Stewart, the movie focuses on the one who actually ran away, lead singer Cherie Currie, a kohl-eyed and sullen Dakota Fanning.