LogsExportCursor was only used by ExportLogsTaskServlet, which we removed a long time ago. It's just dead code. The PersistedRangeLong type was only written for use by LogsExportCursor, and since it hasn't picked up new users in 3+ years I don't think we need to keep it around.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=169264994