Remove instances of KernelVersion::current().unwrap()

[alessandrod]

In a bunch of places we do if KernelVersion::current().unwrap() >= KernelVersion::new(....) {

In theory, we should always know the kernel version so the unwrap is understandable. However it seems that distributions really like to mess with how the kernel version is reported and we've had this unwrap fail in more than one case (some version of ubuntu and recently proxmox).

In the cases where we have if version { ... } else { ... } we should handle the case where current() fails, log a warning, and probably do the else thing which is usually whatever is supported by older kernels.

[pythops]

I have started working on this one.
What do you mean by log a warning ? would eprintln! with a message work or should we include tracing crate ?

[alessandrod]

I have started working on this one.

Awesome thanks!

What do you mean by log a warning ? would eprintln! with a message work or should we include tracing crate ?

We use the log crate, so you can

use log::warn;

warn!("some warning message");