ServeMux depends on having a URL
in order to mux.  It might be that the right
fix is to have CONNECT handlers just not
look at URL.

««« original CL description
http: do not parse req.URL for CONNECT

CONNECT's argument is not a URL.

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/4808044

»»»

TBR=bradfitz
CC=golang-dev
https://golang.org/cl/4798046