misc/dist: use go.tools release branch
misc/dist: use go.tools release branch

R=golang-dev, dsymonds
CC=golang-dev
https://codereview.appspot.com/15450047

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