Investigate random failures in src/flexvolume/attach.py:158

[dzolnierz]

                # Make sure task is completed
                task = Client.ctx.client.get_task_monitor().wait_for_status(
                    task=is_disk_attached,
                    timeout=60,
                    poll_frequency=2,
                    fail_on_statuses=None,
                    expected_target_statuses=[
                        TaskStatus.SUCCESS, TaskStatus.ABORTED, TaskStatus.ERROR,
                        TaskStatus.CANCELED
                    ],
                    callback=None)
                # Sometimes task "fails" with error:
                # majorErrorCode=500 and message=Unable to perform this action.
                assert task.get('status') == TaskStatus.SUCCESS.value