Remove raw pointer from OpenOptions struct

Otherwise it is not Send and Sync anymore

src/libstd/fs.rs

@@ -2264,6 +2264,12 @@ mod tests {
         assert_eq!(check!(fs::metadata(&tmpdir.join("h"))).len(), 9);
     }
 
+    #[test]
+    fn _assert_send_sync() {
+        fn _assert_send_sync<T: Send + Sync>() {}
+        _assert_send_sync::<OpenOptions>();
+    }
+
     #[test]
     fn binary_file() {
         let mut bytes = [0; 1024];