goinstall: warn when http:// is found at beginning of package name Fixes issue 860.
goinstall: warn when http:// is found at beginning of package name
Fixes issue 860.

R=golang-dev, adg1, rsc, adg
CC=golang-dev
http://codereview.appspot.com/2124046

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