goplay: fix to run under windows.
goplay: fix to run under windows.

Fixes issue 1204.

R=golang-dev, brainman, Joe Poirier, alex.brainman, adg
CC=golang-dev, math-nuts
http://codereview.appspot.com/2532041

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

Triskite/willstone-goclone,npe9/noahevans-go9,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,npe9/noahevans-go9,mhennings/marcohennings-go,rdp/rogerpack2005-golang,bryanxu/go-zh,scirelli/scirelli-go,d0f/go-zh,sanjosh/sanjos100-tipc,scirelli/scirelli-go,rdp/rogerpack2005-golang,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,mhennings/marcohennings-go,rflanagan/reginaldflanagan-project1,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,d0f/go-zh,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,rflanagan/reginaldflanagan-project1,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,npe9/noahevans-go9,webfd/go-zh,rdp/rogerpack2005-golang,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,Triskite/willstone-goclone,webfd/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,webfd/go-zh,sanjosh/sanjos100-tipc,Triskite/willstone-goclone,webfd/go-zh,bryanxu/go-zh,webfd/go-zh,d0f/go-zh,webfd/go-zh,Triskite/willstone-goclone,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,scirelli/scirelli-go,npe9/noahevans-go9,webfd/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,scirelli/scirelli-go,d0f/go-zh,Triskite/willstone-goclone,Triskite/willstone-goclone,mhennings/marcohennings-go,scirelli/scirelli-go,webfd/go-zh,d0f/go-zh,mhennings/marcohennings-go,bryanxu/go-zh,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,npe9/noahevans-go9,scirelli/scirelli-go,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,npe9/noahevans-go9,d0f/go-zh,rdp/rogerpack2005-golang,npe9/noahevans-go9,d0f/go-zh,Triskite/willstone-goclone,mhennings/marcohennings-go,npe9/noahevans-go9,rdp/rogerpack2005-golang,mhennings/marcohennings-go,bryanxu/go-zh,sanjosh/sanjos100-tipc