Fix unique index recovery in 2.0

Recovery fails (with "cannot await recovering index") when recovering a store where the active log both creates and drops the index in question.

The proposed fix is to not activate the index during recovery.

The correctness of this is based on the assumption that there are other processes (already in place) to make sure that the indexes are activated post-recovery.

These changes also adds some better diagnostics output in `DumpLogicalLog`, `messages.log`, and the exceptions from a recovering index.