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.
assert(consensus.hashGenesisBlock == uint256S("0x0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"));
        assert(genesis.hashMerkleRoot == uint256S("0x4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"));
        vFixedSeeds.clear(); 
        vSeeds.clear();      
        fDefaultConsistencyChecks = true;
        fRequireStandard = false;
        fMineBlocksOnDemand = true;
        checkpointData = {
            {
                {0, uint256S("0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206")},
            }
        };
        chainTxData = ChainTxData{
            0,
            0,
            0
        };
        base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
        base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);
        base58Prefixes[EXT_PUBLIC_KEY] = {0x04, 0x35, 0x87, 0xCF};
        base58Prefixes[EXT_SECRET_KEY] = {0x04, 0x35, 0x83, 0x94};
        bech32_hrp = "bcrt";
        
        m_fallback_fee_enabled = true;
    }
    /**
     * Allows modifying the Version Bits regtest parameters.
     */
    void UpdateVersionBitsParameters(Consensus::DeploymentPos d, int64_t nStartTime, int64_t nTimeout)