This change fixes resolution of secure (https) repo URL for
git.apache.org Git repositories.

E.g. the correct repo URL for git.apache.org/thrift.git/lib/go/thrift is
https://git.apache.org/thrift.git, not https://git.apache.org/thrift

Fixes #10797

Change-Id: I67d5312ad8620eb780e42c2e002c8f286f60645a
Reviewed-on: https://go-review.googlesource.com/10092Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>