Re-compute / pre-populate compaction heuristics when log/manifest reuse is turned on.

When the log/manifest reuse option is turned on (I forget the specific name, where the log is just loaded into memory and there isn't a repair/compaction), compaction heuristics aren't appropriately set. This means that if a user opens the database, writes up to right 'before' compaction would trigger, and then closes & re-opens the database (and repeats), there is a never-ending growing log file w/o any compaction until OOM.