change log index should be in separate table

The index of a change log entry is retrieved from the max index in the change log entry table. However, the change log table deletes old records. If the table is cleared out (not sure if the daemon that clears old records will do this or not), then the index might start over at 1. But consumers will stop pulling records since they keep track of the last number. Anyways, it will probably be safer if this is in a different table and updated periodically...