Preserve as much of the redirect URL as possible

Discard only the portion of the redirect_url _after_ the host and port, which 
will exclude the scheme, host, and port while preserving path, query, and
fragment.

    http://foo.com:1234/posts?id=30&limit=5#time=1305298413

is transformed to

    /posts?id=30&limit=5#time=1305298413