param: remove old callback code

Cleaned up remaining code. Reduced comment noise. Reverted
macro names back to the original.

Signed-off-by: Mark Beckwith <wythe@intrig.com>

lightningd/log.c

@@ -666,7 +666,7 @@ static void json_getlog(struct command *cmd,
 	struct log_book *lr = cmd->ld->log_book;
 
 	if (!param(cmd, buffer, params,
-		   p_opt_def_tal("level", json_tok_loglevel, &minlevel,
+		   p_opt_def("level", json_tok_loglevel, &minlevel,
 				 LOG_INFORM),
 		   NULL))
 		return;