doc: fix concurrency patterns rawhtml generation
doc: fix concurrency patterns rawhtml generation

The Makefile target was broken due to the rename of the HTML file.

R=golang-dev
CC=golang-dev
http://codereview.appspot.com/5918045

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

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