Those domains are available over HTTPS and we should use them to
ensure privacy and message integrity, particularly in the cases where
we are updating the Unicode table.

Change-Id: I861aa1f581034a762e201ba07faf0e106d231eb3
Reviewed-on: https://go-review.googlesource.com/127918


Run-TryBot: Kevin Burke <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Brad Fitzpatrick <[email protected]>