[Virtio-fs] [virtiofsd-rs] MR opened: Apply cargo fmt and clippy suggestions

[virtiofs-bot at sinrega.org]

It looks like my local versions of *rustfmt* and *clippy* are perhaps newer than the ones we use for CI, and so they recommend changes that our CI run does not.  (Although *rustfmt* in the CI run complans with “Warning: can't set `imports_granularity = Module`, unstable features are only available in nightly channel.�)

Perhaps we should also update these tools in our CI containers, but I don’t know whether that’s even possible (other than just waiting for newer versions to be available there).
---
https://gitlab.com/virtio-fs/virtiofsd/-/merge_requests/57