### 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

{
    CWallet * const pwallet = GetWalletForJSONRPCRequest(request);
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 0)
        throw std::runtime_error(
                "getunconfirmedbalance\n"
                "Returns the server's total unconfirmed balance\n");
    ObserveSafeMode();
    LOCK2(cs_main, pwallet->cs_wallet);
    return ValueFromAmount(pwallet->GetUnconfirmedBalance());
}
UniValue movecmd(const JSONRPCRequest& request)
{
    CWallet * const pwallet = GetWalletForJSONRPCRequest(request);
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() < 3 || request.params.size() > 5)
        throw std::runtime_error(
            "move \"fromaccount\" \"toaccount\" amount ( minconf \"comment\" )\n"
            "\nDEPRECATED. Move a specified amount from one account in your wallet to another.\n"
            "\nArguments:\n"
            "1. \"fromaccount\"   (string, required) The name of the account to move funds from. May be the default account using \"\".\n"
            "2. \"toaccount\"     (string, required) The name of the account to move funds to. May be the default account using \"\".\n"
            "3. amount            (numeric) Quantity of " + CURRENCY_UNIT + " to move between accounts.\n"
            "4. (dummy)           (numeric, optional) Ignored. Remains for backward compatibility.\n"