go spec: clarifying variable declaractions w/ constants
go spec: clarifying variable declaractions w/ constants

Fixes issue 2377.

R=r, rsc
CC=golang-dev
http://codereview.appspot.com/5267048

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang