gofmt: simpler walkDir
gofmt: simpler walkDir

Swapping the goroutines lets them reuse the
communication completion on v instead of
needing a second channel (done).

R=gri
CC=golang-dev
http://codereview.appspot.com/4287045
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go