do an extra CheckBlock in ConnectBlock

main.cpp

@@ -1107,6 +1107,10 @@ bool CBlock::DisconnectBlock(CTxDB& txdb, CBlockIndex* pindex)
 
 bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex)
 {
+    // Check it again in case a previous version let a bad block in
+    if (!CheckBlock())
+        return false;
+
     //// issue here: it doesn't know the version
     unsigned int nTxPos = pindex->nBlockPos + ::GetSerializeSize(CBlock(), SER_DISK) - 1 + GetSizeOfCompactSize(vtx.size());