Options needed for truncating ship data and block logs when starting from snapshot

[cc32d9]

A ship server under 3.1.4 produced some corrupted ship data, and it appears that leap 5.0 does not truncate the state history on starting from snapshot.

So, two command-line options are needed for starting from snapshot:

1. One for truncating the blocks log at the snapshot block
2. One for truncating the state history logs at the snapshot block