In a reneg use the same client_version we used last time

In 1.0.2 and below we always send the same client_version in a reneg
ClientHello that we sent the first time around, regardless of what
version eventually gets negotiated. According to a comment in
statem_clnt.c this is a workaround for some buggy servers that choked if
we changed the version used in the RSA encrypted premaster secret.

In 1.1.0+ this behaviour no longer occurs. This restores the original
behaviour.

Fixes #1651

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6059)