jsonrpc: current pending commands are not a leak.

The pay command in particular, attaches a reasonable number of
temporaries to cmd, knowing they'll be freed once cmd is done.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/jsonrpc.c

@@ -441,6 +441,8 @@ void command_fail(struct command *cmd, const char *fmt, ...)
 
 void command_still_pending(struct command *cmd)
 {
+	notleak_with_children(cmd);
+	notleak(cmd->jcon);
 	cmd->pending = true;
 }