os: remove race paranoia from Environ(); it's guarded now
os: remove race paranoia from Environ(); it's guarded now

R=rsc
CC=golang-dev
http://codereview.appspot.com/4426077

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

ssrl/go,ssrl/go,tv42/old-go,dsriram/golang,dsriram/golang,tv42/old-go,gnanderson/go,pombredanne/go-deleteme,pombredanne/go-deleteme,gnanderson/go,gnanderson/go,dsriram/golang,apparentlymart/golang,gnanderson/go,pombredanne/go-deleteme,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,pombredanne/go-deleteme,tv42/old-go,apparentlymart/golang,gnanderson/go,ssrl/go,dsriram/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,dsriram/golang,tv42/old-go,gnanderson/go,tv42/old-go,ssrl/go,ssrl/go,ssrl/go,dsriram/golang,gnanderson/go,ssrl/go,tv42/old-go,apparentlymart/golang,apparentlymart/golang