Bugfix CValidationResult for BIP30 + add DoS

src/main.cpp

@@ -1605,7 +1605,7 @@ bool CBlock::ConnectBlock(CValidationState &state, CBlockIndex* pindex, CCoinsVi
         for (unsigned int i=0; i<vtx.size(); i++) {
             uint256 hash = GetTxHash(i);
             if (view.HaveCoins(hash) && !view.GetCoins(hash).IsPruned())
-                return error("ConnectBlock() : tried to overwrite transaction");
+                return state.DoS(100, error("ConnectBlock() : tried to overwrite transaction"));
         }
     }