Moving TLS 1.3 version negotiation into extension.

Change-Id: I73f9fd64b46f26978b897409d817b34ec9d93afd
Reviewed-on: https://boringssl-review.googlesource.com/11080
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/include/openssl/tls1.h b/include/openssl/tls1.h
index 3c97d26..eca5dec 100644
--- a/include/openssl/tls1.h
+++ b/include/openssl/tls1.h
@@ -209,16 +209,9 @@
 #define TLSEXT_TYPE_key_share 40
 #define TLSEXT_TYPE_pre_shared_key 41
 #define TLSEXT_TYPE_early_data 42
+#define TLSEXT_TYPE_supported_versions 43
 #define TLSEXT_TYPE_cookie 44
 
-/* TLSEXT_TYPE_draft_version is the extension used to advertise the TLS 1.3
- * draft implemented.
- *
- * See
- * https://github.com/tlswg/tls13-spec/wiki/Implementations#version-negotiation
- */
-#define TLSEXT_TYPE_draft_version 0xff02
-
 /* ExtensionType value from RFC5746 */
 #define TLSEXT_TYPE_renegotiate 0xff01