Always use TLSv1.0 for record layer version in TLSv1.3

TLSv1.3 freezes the record layer version and ensures that it is always set
to TLSv1.0. Some implementations check this.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2157)

ssl/record/rec_layer_s3.c

@@ -784,7 +784,7 @@ int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
     /* Clear our SSL3_RECORD structures */
     memset(wr, 0, sizeof wr);
     for (j = 0; j < numpipes; j++) {
-        unsigned int version = s->version;
+        unsigned int version = SSL_IS_TLS13(s) ? TLS1_VERSION : s->version;
         unsigned char *compressdata = NULL;
         size_t maxcomplen;
         unsigned int rectype;