Bugfix (introduced: Postfix 3.1): "postfix tls deploy-server-cert" did not
handle a missing optional argument.

Bugfix (introduced: Postfix 3.4): in the Postfix SMTP server, the SNI
callback reported an error when it was called a second time. This happened
after the server-side TLS engine sent a TLSv1.3 HelloRetryRequest (HRR) to
a remote SMTP client.