fix bug in $GOROOT handling: error calling Getenv.
fix bug in $GOROOT handling: error calling Getenv.

R=gri
OCL=31047
CL=31047

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