spec: add parens missing from "protect" example. Fixes issue 1665.
spec: add parens missing from "protect" example.
Fixes issue 1665.

R=gri
CC=golang-dev
http://codereview.appspot.com/4351051

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