Ties de Wit

This is my output when running your code ``` unix.Statfs_t{Type:12805120, Bsize:4194304, Blocks:0x6400, Bfree:0x45e8, Bavail:0x45e8, Files:0x211170, Ffree:0xffffffffffffffff, Fsid:unix.Fsid{Val:[2]int32{-1469057901, -1}}, Namelen:255, Frsize:4194304, Flags:1056, Spare:[4]int64{0, 0, 0, 0}} ``` or more readable `fmt.Printf("%+v\n",...

I believe this is where is goes wrong with my `Files:2167163` & `Ffree:18446744073709551615`: https://github.com/shirou/gopsutil/blob/ed37dc27a286a25cbe76adf405176c69191a1f37/disk/disk_unix.go#L21-L33