net/http: set cookies in client jar on POST requests.
net/http: set cookies in client jar on POST requests.

Cookies recieved in a response to a POST request are stored
in the client's jar like they are for GET requests.

R=golang-dev, rsc
CC=bradfitz, golang-dev
http://codereview.appspot.com/5576065

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go