fixup! json: Only start parsing once we're sure we have a message

lightningd/plugin.c

@@ -501,7 +501,7 @@ static struct io_plan *plugin_read_json(struct io_conn *conn,
 	 * overlap if we're not at the start) to see if we have a '\n\n'
 	 * separator. If not we can skip the JSON attempt. */
 	have_full = memmem(plugin->buffer + plugin->used - offset,
-			   plugin->len_read + offset, "\n\n", 2);
+			   plugin->len_read + offset, "}\n", 2);
 
 	plugin->used += plugin->len_read;
 	if (plugin->used == tal_count(plugin->buffer))