Streaming txmeta omits genesis ledger

[graydon]

The genesis ledger built in LedgerManagerImpl::startNewLedger calls ledgerClosed directly, rather than synthesizing a LedgerCloseData and calling closeLedger, which means that we do not stream txmeta for the genesis ledger. We should.

[dmkozh]

This proved to be much more tricky than it seems at a first glance, as it's not clear what the meta should be. Tt needs to be special-cased and it's not clear how valuable is one-off special meta that would also need some special downstream handling.