This commit erroneously kept the DTLS timer running after the end of the
handshake. This is not correct behaviour and shold be reverted.
This reverts commit f7506416b1311e65d5c440defdbcfe176f633c50.
Fixes#7998
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8047)