### 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() > 2)
        throw std::runtime_error(
            "listaccounts ( minconf include_watchonly)\n"
            "\nDEPRECATED. Returns Object that has account names as keys, account balances as values.\n"
            "\nArguments:\n"
            "1. minconf             (numeric, optional, default=1) Only include transactions with at least this many confirmations\n"
            "2. include_watchonly   (bool, optional, default=false) Include balances in watch-only addresses (see 'importaddress')\n"
            "\nResult:\n"
            "{                      (json object where keys are account names, and values are numeric balances\n"
            "  \"account\": x.xxx,  (numeric) The property name is the account name, and the value is the total balance for the account.\n"