mysqld_upgrade --check-if-upgrade-is-needed leaks files

Hi,

we discovered that mysql_upgrade with check-if-upgrade-is-needed leaks files under the tmp directory. It will like always create the mysql_upgrade-****** defaults-file but never clean it up.

should easily be fixable by something like that:

  if (opt_check_upgrade)

    free_used_memory();

    exit(upgrade_already_done(0) == 0);

see code