Display a login success message

[knqyf263]

I'd like to know the person who logged in by google-authenticator. sshd displays only the following message

Nov 16 14:37:57 test01 sshd[30165]: Accepted keyboard-interactive/pam for knqyf263 from 192.168.1.10 port 52712 ssh2

[googlebot]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

:memo: Please visit https://cla.developers.google.com/ to sign.

Once you've signed, please reply here (e.g. I signed it!) and we'll verify. Thanks.

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• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If you signed the CLA as a corporation, please let us know the company's name.

[knqyf263]

I signed it!

[googlebot]

CLAs look good, thanks!

[ThomasHabets]

Thanks!