Inconsistent implementation of Filesystem::files for FreeBSD and Linux

[warrenfalk]

FreeBSD is implemented like this:

Filesystem {
    files: self.f_files as usize - self.f_ffree as usize,
    /* ... */
}

Linux is implemented like this:

Filesystem {
    files: info.f_files as usize,
    /* ... */
}

So the same field, Filesystem::files, actually has different meanings in each platform. I assume Linux is wrong here because it isn't actually very useful to have only the capacity. I plan to submit a PR for this

[valpackett]

Yeah, looking at the man pages, f_files appears to mean the same thing on both platforms.