We misread (or maybe it changed?) the draft padding scheme. The current
text does not round the whole payload to a multiple of 32, just the
server name as a fallback. Switch the GREASE size selection to match.
Although, we may want to change the draft here. See also
https://github.com/tlswg/draft-ietf-tls-esni/issues/433
While I'm here, update some references from draft-09 to draft-10. Also
make the comment less verbose.
Bug: 275
Change-Id: I3c9f34159890bc3b7d71f6877f34b895bc7f9b17
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/47644
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>