message: Expand error-message when a valid export is not found at the specified export location in bundle-shim.
diff: @@ -371,9 +371,15 @@ Status LoadSessionBundleOrSavedModelBundle(
  return LoadSavedModelFromLegacySessionBundlePath(
  session_options, run_options, export_dir, saved_model_bundle);
  }
  - return Status(error::Code::NOT_FOUND,
  - "Session bundle or SavedModel bundle not found at specified "
  - "export location");
  + return Status(
  + error::Code::NOT_FOUND,
  + strings::StrCat(
  + "Specified file path does not appear to contain a:\n"
  + "- Session bundle (should have a file called `export.meta`)\n"
  + "- or, SavedModel bundle (should have a file called "
  + "`saved_model.pb`)\n"
  + "Specified file path: ",
  + export_dir));
  }
  } // namespace serving
  