message: Fix a potential segfault / race in tests
diff: @@ -59,11 +59,11 @@ mod tests {
  #[test]
  pub fn test_get_h5_str() {
  - let s = unsafe {
  + let s = h5call!({
  get_h5_str(|msg, size| {
  H5Eget_msg(*H5E_CANTOPENOBJ, ptr::null_mut(), msg, size)
  }).ok().unwrap()
  - };
  + });
  assert_eq!(s, "Can't open object");
  }
  }
  