goinstall: abort and warn when using any url scheme, not just 'http://'
goinstall: abort and warn when using any url scheme, not just 'http://'

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/4801053
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go