go spec: fix inaccuracy in type identity definition
go spec: fix inaccuracy in type identity definition

Pointed out by Steven Blenkinsop (steven099@gmail.com)
via golang-nuts.

R=r, dsymonds
CC=golang-dev
http://codereview.appspot.com/5783087
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go