nacl: use HTTPS for nacl.cr.yp.to links

nacl.cr.yp.to is available over HTTPS and presents a valid certificate, so
seems useful to use it.

Change-Id: I64d86e52cc314641b4169167fe5123d38c2904c0
Reviewed-on: https://go-review.googlesource.com/26812
Reviewed-by: Jonathan Rudenberg <jonathan@titanous.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2 files changed