Fix the TLS 1.3 obfuscated_ticket_age caclulation

Summary: Courtesy to Bill Warshaw. Fix the calcuation of obfuscated_ticket_age, it is milliseconds.

Test Plan:

tests/ssl-opt.sh

Reviewers:

Subscribers:

Tasks:

Tags:

Notes:

Pull requests cannot be accepted until the PR follows the contributing guidelines. In particular, each commit must have at least one Signed-off-by: line from the committer to certify that the contribution is made under the terms of the Developer Certificate of Origin.
This is just a template, so feel free to use/remove the unnecessary things
Description

A few sentences describing the overall goals of the pull request's commits.

Status

READY/IN DEVELOPMENT/HOLD

When there is a bug fix, it should be backported to all maintained and supported branches. Changes do not have to be backported if:

This PR is a new feature\enhancement
This PR contains changes in the API. If this is true, and there is a need for the fix to be backported, the fix should be handled differently in the legacy branch

Yes | NO
Which branch?

If there is any API change, what's the incentive and logic for it.

YES | NO

Any additional information that could be of interest

Outline the steps to test or reproduce the PR here.