goinstall: don't wrongly error out with "multiple package names"
goinstall: don't wrongly error out with "multiple package names"

Fixes issue 1215.

R=adg, rsc
CC=golang-dev
http://codereview.appspot.com/2695042

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go