The new logic is:
        If (HEAD)       /* happens only on pass */
                do not fetch body.
        else if (Content-Length)
                fetch body according to length
        else if (chunked)
                fetch body as chunked
        else if (other transfer-encoding)
                fail
        else if (Connection: keep-alive)
                fetch no body, set Length = 0
        else if (Connection: close)
                fetch body until EOF
        else if (HTTP < 1.1)
                fetch body until EOF
        else
                fetch no body, set Length = 0

let me know if this breaks anything that should work.

Fixes #400



git-svn-id: http://www.varnish-cache.org/svn/branches/2.0@3663 d4fa192b-c00b-0410-8231-f00ffab90ce4