sys: fs: derive Copy for CreateOptions

Pretty much all functions accepting `CreateOptions` take a value and not
a reference, so I've found myself using `.clone()` quite often in code
I've written recently.
The struct is only 24 bytes large (verified by a
`std::mem::size_of::<CreateOptions>()`), so it should be absolutely fine
to just derive Copy for it.

Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>

proxmox-sys/src/fs/mod.rs

@@ -30,7 +30,7 @@ pub fn fchown(fd: RawFd, owner: Option<Uid>, group: Option<Gid>) -> Result<(), E
 }
 
 /// Define permissions, owner and group when creating files/dirs
-#[derive(Clone, Default)]
+#[derive(Copy, Clone, Default)]
 pub struct CreateOptions {
     perm: Option<stat::Mode>,
     owner: Option<Uid>,