Linux Virtualization: Use the new nests `systems` format for lxd / lxc
Linux Virtualization: Use the new nests `systems` format for lxd / lxc

Somehow we never updated these for the new format. This means you can end up with data like this which is wrong in both the legacy and the new format.

```json
{
  "systems": {
    "xen": "guest"
  },
  "system": "lxd",
  "role": "host"
}
```

with this change we get:

```json
{
  "systems": {
    "xen": "guest",
    "lxd": "host"
  },
  "system": "lxd",
  "role": "host"
}
```

Signed-off-by: Tim Smith <764ef62106582a09ed09dfa0b6bff7c05fd7d1e4@chef.io>

mattray/ohai,mattray/ohai,jaymzh/ohai,chef/ohai,chef/ohai,higanworks/ohai,jaymzh/ohai,higanworks/ohai