container/list: fix typo
container/list: fix typo

R=golang-dev, fullung, dave, minux.ma
CC=golang-dev
http://codereview.appspot.com/6682046

Committer: Nigel Tao <58ae08b3356928ff9c67562b4719487d54fe8348@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang