Don't forcibly remove parted etc. on VMs.

Our automated test suite *needs* parted, so currently we're
uninstalling parted just to reinstall it later every 30 minutes or so.

This partially reverts 54d9d6ae,
which I initially committed mainly to get smartd out of the way on VMs.
It's no big deal to have memlockd, memtest86+ and parted on VMs.