verification.cpp update variables to be const

    We don't want these to change.
    Fixes issue #800.

Author: fdoving

src/validation.cpp

@@ -4938,9 +4938,9 @@ bool CVerifyDB::VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview,
         if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
             return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
         // check level 1: verify block validity
-        bool fCheckPoW = true;
-        bool fCheckMerkleRoot = true;
-        bool fDBCheck = true;
+        const bool fCheckPoW = true;
+        const bool fCheckMerkleRoot = true;
+        const bool fDBCheck = true;
         if (nCheckLevel >= 1 && !CheckBlock(block, state, chainparams.GetConsensus(), fCheckPoW, fCheckMerkleRoot, fDBCheck)) // fCheckAssetDuplicate set to false, because we don't want to fail because the asset exists in our database, when loading blocks from our asset databse
             return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__,
                          pindex->nHeight, pindex->GetBlockHash().ToString(), FormatStateMessage(state));