Contrary to ERP5, there's no mysql-update service:
- this simplifies the SR
- after reading the MySQL documentation, the automatic use of mysql_upgrade
  is quite frightening:
  « You should always back up your current MySQL installation before performing
  an upgrade. »
  « After running mysql_upgrade, stop the server and restart it so that any
  changes made to the system tables take effect. » (which is currently not done
  by the recipe)
- the future of NEO is an embedded DB like libmysqld