math: remove repeated comment.
math: remove repeated comment.

R=golang-dev, nigeltao
CC=golang-dev
https://codereview.appspot.com/7835046

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

d0f/go-zh,mhennings/marcohennings-go,mhennings/marcohennings-go,rdp/rogerpack2005-golang,webfd/go-zh,scirelli/scirelli-go,webfd/go-zh,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,bryanxu/go-zh,webfd/go-zh,scirelli/scirelli-go,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,d0f/go-zh,bryanxu/go-zh,webfd/go-zh,rdp/rogerpack2005-golang,webfd/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,scirelli/scirelli-go,scirelli/scirelli-go,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,scirelli/scirelli-go,bryanxu/go-zh,d0f/go-zh,scirelli/scirelli-go,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,mhennings/marcohennings-go,mhennings/marcohennings-go,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,d0f/go-zh,d0f/go-zh,webfd/go-zh,rdp/rogerpack2005-golang,bryanxu/go-zh,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,webfd/go-zh,d0f/go-zh,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc