message: don't shutdown when db contains now defunct blocks that fail stake modifier checkpoint
diff: @@ -3065,13 +3065,13 @@ bool static LoadBlockIndexDB()
  pindex->nChainTrust = (pindex->pprev ? pindex->pprev->nChainTrust : 0) + pindex->GetBlockTrust().getuint256();
  // ppcoin: calculate stake modifier checksum
  pindex->nStakeModifierChecksum = GetStakeModifierChecksum(pindex);
  - if (!CheckStakeModifierCheckpoints(pindex->nHeight, pindex->nStakeModifierChecksum))
  - return error("LoadBlockIndexDB() : Failed stake modifier checkpoint height=%d, modifier=0x%016" PRI64x, pindex->nHeight, pindex->nStakeModifier);
  -
  + if (CheckStakeModifierCheckpoints(pindex->nHeight, pindex->nStakeModifierChecksum)) {
  pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
  if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS && !(pindex->nStatus & BLOCK_FAILED_MASK))
  setBlockIndexValid.insert(pindex);
  }
  + else printf("LoadBlockIndexDB() : Failed stake modifier checkpoint height=%d, modifier=0x%016" PRI64x ", sum=0x%016" PRI64x, pindex->nHeight, pindex->nStakeModifier, pindex->nStakeModifierChecksum);
  + }
  // Load block file info
  pblocktree->ReadLastBlockFile(nLastBlockFile);
  