### Describe the issue

I added a second new wallet2.dat. Now I wanted to encrypt it, but `bitcoin-cli help` does not show the command to do so, I need to use `bitcoin-cli -rpcwallet=wallet2.dat help`. This is very un-intuitive, and bad for a help function.

### Can you reliably reproduce the issue?

1. have an encrypted default wallet
2. add new multi wallet wallet2.dat via config file or cmd line options
3. naive `bitcoin-cli help` does not show command to encrypt second wallet.

### Expected behaviour

All wallet encryption, lock and unlock commands should be shown unconditionally in `bitcoin-cli help`.

The dynamic hiding of some lines is arguably worse than the benefit with multiple wallets.

### Actual behaviour

`bitcoin-cli help` shows only wallet encryption commands appropriate for the default wallet.

### What version of bitcoin-core are you using?

bitcoind 0.15.0.1~dfsg-1
deb http://ppa.launchpad.net/luke-jr/bitcoin-core-bip148-unofficial-builds/ubuntu zesty main

### Machine specs:
- OS: Debian 9.2

});
        std::string txid = find_value(o, "txid").get_str();
        if (!IsHex(txid))
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, expected hex txid");
        int nOutput = find_value(o, "vout").get_int();
        if (nOutput < 0)
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout must be positive");
        COutPoint outpt(uint256S(txid), nOutput);
        if (fUnlock)
            pwallet->UnlockCoin(outpt);
        else
            pwallet->LockCoin(outpt);
    }
    return true;
}
UniValue listlockunspent(const JSONRPCRequest& request)
{
    CWallet * const pwallet = GetWalletForJSONRPCRequest(request);
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 0)
        throw std::runtime_error(
            "listlockunspent\n"
            "\nReturns list of temporarily unspendable outputs.\n"
            "See the lockunspent call to lock and unlock transactions for spending.\n"
            "\nResult:\n"
            "[\n"
            "  {\n"
            "    \"txid\" : \"transactionid\",     (string) The transaction id locked\n"