Using a Bitcoin-Qt v0.16.0 ([downloaded from bitcoin page](https://bitcoin.org/bin/bitcoin-core-0.16.0/bitcoin-0.16.0-osx.dmg)) in an macOS High Sierra 10.13.4 

When I start after a fresh install Bitcoin-Qt as a mainnet node and wallet, the wallet prompt that about 203gb is going to be used in my disk
![image](https://user-images.githubusercontent.com/20187136/39899688-ba820bfe-5493-11e8-87d9-460ed5716a02.png)

When I start the node and wallet as testnet, shows the same message about the 203gb disk usage
![image](https://user-images.githubusercontent.com/20187136/39899756-17b31214-5494-11e8-8a57-60e604e74afb.png)

It seems that the second time the message is wrong, due that the testnet database uses about 14gb.
UniValue executeRpc(const std::string& command, const UniValue& params, const std::string& uri) override
    {
        JSONRPCRequest req;
        req.params = params;
        req.strMethod = command;
        req.URI = uri;
        return ::tableRPC.execute(req);
    }
    std::vector<std::string> listRpcCommands() override { return ::tableRPC.listCommands(); }
    void rpcSetTimerInterfaceIfUnset(RPCTimerInterface* iface) override { RPCSetTimerInterfaceIfUnset(iface); }
    void rpcUnsetTimerInterface(RPCTimerInterface* iface) override { RPCUnsetTimerInterface(iface); }
    bool getUnspentOutput(const COutPoint& output, Coin& coin) override
    {
        LOCK(::cs_main);
        return ::pcoinsTip->GetCoin(output, coin);
    }
    std::vector<std::unique_ptr<Wallet>> getWallets() override
    {
        std::vector<std::unique_ptr<Wallet>> wallets;
        for (const std::shared_ptr<CWallet>& wallet : GetWallets()) {
            wallets.emplace_back(MakeWallet(wallet));
        }
        return wallets;
    }
    std::unique_ptr<Handler> handleInitMessage(InitMessageFn fn) override