blockchain: Initialize database with genesis block.
blockchain: Initialize database with genesis block.

This fixes a bug introduced by #1066.
aakselrod/btcd,tb00/btcd,ltcsuite/ltcd,davecgh/btcd,dajohi/btcd,ppcsuite/ppcd,dajohi/btcd,wallclockbuilder/btcd,btcsuite/btcd,tb00/btcd,ltcsuite/ltcd,davecgh/btcd,ppcsuite/ppcd,aakselrod/btcd,wallclockbuilder/btcd,dajohi/btcd,btcsuite/btcd