Convert the Channel ID extension to the new system.

This also removes support for the “old” Channel ID extension.

Change-Id: I1168efb9365c274db6b9d7e32013336e4404ff54
Reviewed-on: https://boringssl-review.googlesource.com/5462
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/tls1.h b/include/openssl/tls1.h
index ad8c130..b3be3e1 100644
--- a/include/openssl/tls1.h
+++ b/include/openssl/tls1.h
@@ -239,8 +239,7 @@
 #define TLSEXT_TYPE_next_proto_neg 13172
 
 /* This is not an IANA defined extension number */
-#define TLSEXT_TYPE_channel_id 30031
-#define TLSEXT_TYPE_channel_id_new 30032
+#define TLSEXT_TYPE_channel_id 30032
 
 /* NameType value from RFC 3546 */
 #define TLSEXT_NAMETYPE_host_name 0