build: remove old version*.go files from hgignore
build: remove old version*.go files from hgignore

This broke a build on a Linux box I hadn't updated
in awhile. The hgignore files were preventing hg status
from showing and hg purge from cleaning up junk.

R=golang-dev, dsymonds
CC=golang-dev
http://codereview.appspot.com/5687048
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go