http: cleaned up HEAD request method.
http: cleaned up HEAD request method.

Removed a redefinition of the request URL which is never used and
redundant checking of the return value from send().

R=golang-dev, adg
CC=golang-dev
http://codereview.appspot.com/4184061

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

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