Failed to open file “/sys/block//queue/rotational”:

## Prerequisites
- [x] I have searched open and closed issues for duplicates.

## Describe the bug
When I open About plug in a Switchboard, I see the following error in the journal:

```
Mar 24 02:09:17 nixos .io.elementary.[1726]: HardwareView.vala:307: Failed to open file “/sys/block//queue/rotational”: No such file or directory
```

### Expected behaviour
No error is logged.

## Platform Information

- OS: NixOS
- About plug version 2.6.1
- QEMU VM

- [ ] I'm using the latest version from git that I've manually compiled
- [x] I'm using the latest released stable version

## Additional context

Using `strace -f -e trace=%process io.elementary.switchboard` I recovered the following commands (both exiting with 0 status). Here is the output of running them in terminal:

```
[jtojnar@nixos:~]$ df /
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/vda 8191416 1875880 5879724 25% /

[jtojnar@nixos:~]$ lsblk -no pkname /dev/vda

```