message: Add check for genesis block when finalizing
  We don't want to mark the genesis block as invalid so skip
  the IsValid(BLOCK_VALID_CHAIN) when checking the geneisis block
  in FinalizeBlockInternal().
diff: @@ -3913,6 +3913,7 @@ bool ProcessNewBlock(CValidationState &state,
  static bool FinalizeBlockInternal(CValidationState &state, CBlockIndex *pindex)
  {
  + if (pindex != chainActive.Genesis())
  {
  READLOCK(cs_mapBlockIndex);
  if (!pindex->IsValid(BLOCK_VALID_CHAIN))
  