message: Flag git zlib errors as spurious errors
  This may be a bad band-aid for now, but the goal is to help
  address where this has been showing up in the wild quite a lot.
diff: @@ -36,7 +36,7 @@ impl<'a> Retry<'a> {
  fn maybe_spurious(err: &Error) -> bool {
  if let Some(git_err) = err.downcast_ref::<git2::Error>() {
  match git_err.class() {
  - git2::ErrorClass::Net | git2::ErrorClass::Os => return true,
  + git2::ErrorClass::Net | git2::ErrorClass::Os | git2::ErrorClass::Zlib => return true,
  _ => (),
  }
  }
  