### 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() != 1)
        throw std::runtime_error(
            "getaccountaddress \"account\"\n"
            "\nDEPRECATED. Returns the current Bitcoin address for receiving payments to this account.\n"
            "\nArguments:\n"
            "1. \"account\"       (string, required) The account name for the address. It can also be set to the empty string \"\" to represent the default account. The account does not need to exist, it will be created and a new address created  if there is no account by the given name.\n"
            "\nResult:\n"
            "\"address\"          (string) The account bitcoin address\n"
            "\nExamples:\n"
            + HelpExampleCli("getaccountaddress", "")
            + HelpExampleCli("getaccountaddress", "\"\"")
            + HelpExampleCli("getaccountaddress", "\"myaccount\"")
            + HelpExampleRpc("getaccountaddress", "\"myaccount\"")
        );
    LOCK2(cs_main, pwallet->cs_wallet);
    
    std::string strAccount = AccountFromValue(request.params[0]);
    UniValue ret(UniValue::VSTR);
    ret = EncodeDestination(GetAccountAddress(pwallet, strAccount));
    return ret;
}
UniValue getrawchangeaddress(const JSONRPCRequest& request)