SSL: workaround for session timeout handling with TLSv1.3.

SSL: workaround for session timeout handling with TLSv1.3.

OpenSSL with TLSv1.3 updates the session creation time on session
resumption and keeps the session timeout unmodified, making it possible
to maintain the session forever, bypassing client certificate expiration
and revocation.  To make sure session timeouts are actually used, we
now update the session creation time and reduce the session timeout
accordingly.

BoringSSL with TLSv1.3 ignores configured session timeouts and uses a
hardcoded timeout instead, 7 days.  So we update session timeout to
the configured value as soon as a session is created.