Fix MariaDB (bump version to 5.5.40 from 5.5.33a)

- fix download URLs
- uploaded artifacts to http://developers.cloudsoftcorp.com/brooklyn/repository/MariaDbNode/5.5.40, so will not break next time mirror removes this version
- live-test stops iptables
quite a significant change here -- dropping `kvm` and switching `amd64` to `x86_64`.  can you confirm?