### 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

ObserveSafeMode();
    LOCK2(cs_main, pwallet->cs_wallet);
    uint256 hash;
    hash.SetHex(request.params[0].get_str());
    isminefilter filter = ISMINE_SPENDABLE;
    if(!request.params[1].isNull())
        if(request.params[1].get_bool())
            filter = filter | ISMINE_WATCH_ONLY;
    UniValue entry(UniValue::VOBJ);
    auto it = pwallet->mapWallet.find(hash);
    if (it == pwallet->mapWallet.end()) {
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid or non-wallet transaction id");
    }
    const CWalletTx& wtx = it->second;
    CAmount nCredit = wtx.GetCredit(filter);
    CAmount nDebit = wtx.GetDebit(filter);
    CAmount nNet = nCredit - nDebit;
    CAmount nFee = (wtx.IsFromMe(filter) ? wtx.tx->GetValueOut() - nDebit : 0);
    entry.push_back(Pair("amount", ValueFromAmount(nNet - nFee)));
    if (wtx.IsFromMe(filter))
        entry.push_back(Pair("fee", ValueFromAmount(nFee)));
    WalletTxToJSON(wtx, entry);
    UniValue details(UniValue::VARR);
    ListTransactions(pwallet, wtx, "*", 0, false, details, filter);
    entry.push_back(Pair("details", details));
    std::string strHex = EncodeHexTx(static_cast<CTransaction>(wtx), RPCSerializationFlags());
    entry.push_back(Pair("hex", strHex));
    return entry;
}
UniValue abandontransaction(const JSONRPCRequest& request)