Navigating forward/backward does not use the redirected url

[mukilan]

Steps to reproduce:
Set RUST_LOG=net

1. Go to http://www.google.co.in
   Log:

DEBUG:net::resource_task: resource_task: loading url: http://www.google.co.in/
INFO:net::http_loader: requesting http://www.google.co.in/
INFO:net::http_loader: got HTTP response 200 OK, headers:
DEBUG:net::image_cache_task: image_cache_task: ended image decode for http://www.google.co.in/images/srpr/logo9w.png
INFO:net::http_loader: got HTTP response 200 OK, headers:
(truncated)

1. Click on "About Google" link. The href of this link is ""http://www.google.co.in/intl/en/about.html"
   However it redirects to ""http://www.google.co.in/intl/en/about/" (no .html at the end)
   Log:

DEBUG:net::resource_task: resource_task: loading url: http://www.google.co.in/intl/en/about.html
INFO:net::http_loader: requesting http://www.google.co.in/intl/en/about.html
INFO:net::http_loader: got HTTP response 301 Moved Permanently, headers:
INFO:net::http_loader:  - Cache-Control: public, max-age=2592000
INFO:net::http_loader:  - Location: http://www.google.co.in/intl/en/about/
INFO:net::http_loader:  - Content-Type: text/html; charset=UTF-8
INFO:net::http_loader:  - X-Content-Type-Options: nosniff
INFO:net::http_loader:  - Expires: Wed, 07 Jan 2015 18:41:45 GMT
INFO:net::http_loader:  - Age: 10022
INFO:net::http_loader:  - Content-Length: 235
INFO:net::http_loader:  - Date: Mon, 08 Dec 2014 18:41:45 GMT
INFO:net::http_loader:  - Alternate-Protocol: 80:quic,p=0.02
INFO:net::http_loader:  - Server: sffe
INFO:net::http_loader:  - X-XSS-Protection: 1; mode=block
INFO:net::http_loader: redirecting to http://www.google.co.in/intl/en/about/
INFO:net::http_loader: requesting http://www.google.co.in/intl/en/about/
INFO:net::http_loader: got HTTP response 200 OK, headers:
(truncated)

1. Press backspace to go back
2. Press shift+backspace to go forward.
   This time Servo loads the about page again from "http://www.google.co.in/intl/en/about.html", gets redirected to "http://www.google.co.in/intl/en/about/"

DEBUG:net::resource_task: resource_task: loading url: http://www.google.co.in/intl/en/about.html
INFO:net::http_loader: requesting http://www.google.co.in/intl/en/about.html
INFO:net::http_loader: got HTTP response 301 Moved Permanently, headers:
INFO:net::http_loader:  - Date: Mon, 08 Dec 2014 18:41:45 GMT
INFO:net::http_loader:  - Alternate-Protocol: 80:quic,p=0.02
INFO:net::http_loader:  - Location: http://www.google.co.in/intl/en/about/
INFO:net::http_loader:  - Age: 10036
INFO:net::http_loader:  - X-Content-Type-Options: nosniff
INFO:net::http_loader:  - Expires: Wed, 07 Jan 2015 18:41:45 GMT
INFO:net::http_loader:  - Content-Length: 235
INFO:net::http_loader:  - X-XSS-Protection: 1; mode=block
INFO:net::http_loader:  - Cache-Control: public, max-age=2592000
INFO:net::http_loader:  - Content-Type: text/html; charset=UTF-8
INFO:net::http_loader:  - Server: sffe
INFO:net::http_loader: redirecting to http://www.google.co.in/intl/en/about/
INFO:net::http_loader: requesting http://www.google.co.in/intl/en/about/
INFO:net::http_loader: got HTTP response 200 OK, headers:
(truncated)

This happens because when we navigate forward/backward, we use the load_data that was created with the original url and is never updated again.