vhost_user: Fix warning about unsafe not needed

There's no need to specify unsafe given the whole function is already
considered unsafe.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

src/vhost_user/connection.rs

@@ -356,7 +356,7 @@ impl<R: Req> Endpoint<R> {
                     .take(n)
                     .map(|fd| {
                         // Safe because we have the ownership of `fd`.
-                        unsafe { File::from_raw_fd(*fd) }
+                        File::from_raw_fd(*fd)
                     })
                     .collect();
                 Some(files)