Pick up the GREASE ECH config ID from grease_seed.

This avoids an unnecessary one-byte RAND_bytes call.

Bug: 275
Change-Id: Idf5bfb17401441f2af7b3c784f7b5d876d005165
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/47989
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/internal.h b/ssl/internal.h
index 7d84312..b3e702b 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1575,7 +1575,8 @@
   ssl_grease_extension2,
   ssl_grease_version,
   ssl_grease_ticket_extension,
-  ssl_grease_last_index = ssl_grease_ticket_extension,
+  ssl_grease_ech_config_id,
+  ssl_grease_last_index = ssl_grease_ech_config_id,
 };
 
 enum tls12_server_hs_state_t {