MEDIUM: http: make option http_proxy automatically rewrite the URL

MEDIUM: http: make option http_proxy automatically rewrite the URL

There are very few users of http_proxy, and all of them complain about
the same thing : the request is passed unmodified to the server (in its
proxy form), and it is not possible to fix it using reqrep rules because
http_proxy happens after.

So let's have http_proxy fix the URL it has analysed to get rid of the
scheme and the host part. This will do what users of this feature expect.