net/http/httputil: permit nil request body in ReverseProxy
Accepting a request with a nil body was never explicitly supported but
happened to work in the past.
This doesn't happen in most cases because usually people pass
a Server's incoming Request to the ReverseProxy's ServeHTTP method,
and incoming server requests are guaranteed to have non-nil bodies.
Still, it's a regression, so fix.
Fixes #12344
Change-Id: Id9a5a47aea3f2875d195b66c9a5f8581c4ca2aed
Reviewed-on: https://go-review.googlesource.com/13935 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>