net/http: Fix nil pointer dereference in error case.
net/http: Fix nil pointer dereference in error case.

R=golang-dev
CC=bradfitz, golang-dev
http://codereview.appspot.com/5598044

Committer: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go