compress/flate: remove unused huffmanEncoder.generateChains.
compress/flate: remove unused huffmanEncoder.generateChains.

R=rsc, gri
CC=golang-dev
http://codereview.appspot.com/5577061

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,bryanxu/go-zh,sanjosh/sanjos100-tipc,rdp/rogerpack2005-golang,d0f/go-zh,scirelli/scirelli-go,scirelli/scirelli-go,webfd/go-zh,Triskite/willstone-goclone,scirelli/scirelli-go,d0f/go-zh,d0f/go-zh,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,bryanxu/go-zh,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,rdp/rogerpack2005-golang,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,scirelli/scirelli-go,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,bryanxu/go-zh,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,sanjosh/sanjos100-tipc,rdp/rogerpack2005-golang,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,Triskite/willstone-goclone,webfd/go-zh,mhennings/marcohennings-go,rdp/rogerpack2005-golang,scirelli/scirelli-go,Triskite/willstone-goclone,mhennings/marcohennings-go,mhennings/marcohennings-go,d0f/go-zh,sanjosh/sanjos100-tipc,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1,bryanxu/go-zh,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,rflanagan/reginaldflanagan-project1,d0f/go-zh,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,bryanxu/go-zh,Triskite/willstone-goclone,mhennings/marcohennings-go,webfd/go-zh,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,scirelli/scirelli-go,webfd/go-zh,mhennings/marcohennings-go,webfd/go-zh,webfd/go-zh,rdp/rogerpack2005-golang,d0f/go-zh