[x/blog] go.blog: add racy example program
[x/blog] go.blog: add racy example program

R=dvyukov, r, remyoudompheng
CC=golang-dev
https://golang.org/cl/10447044
X-Blog-Commit: 235bb198da098068fe79b2cde98062fc1af13d9a

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website