ENG-5960: Fix partition count check on command log replay.

Shouldn't take the max of the cluster's partition count and the partition count
recorded in the snapshot when checking against the partition count in the
command log. If the snapshot has less partition cound, but the cluster has the
same number of partitions as that in the command log, this will use the wrong
snapshot for recovery.

When checking against the command log partition count, always use the one in the
snapshot as reference.
Merge pull request #1170 from VoltDB/ENG-5960

ENG-5960: Fix partition count check on command log replay.