### 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

"  }\n"
            "  ,...\n"
            "]\n"
            "\nExamples:\n"
            + HelpExampleCli("listreceivedbyaccount", "")
            + HelpExampleCli("listreceivedbyaccount", "6 true")
            + HelpExampleRpc("listreceivedbyaccount", "6, true, true")
        );
    ObserveSafeMode();
    LOCK2(cs_main, pwallet->cs_wallet);
    return ListReceived(pwallet, request.params, true);
}
static void MaybePushAddress(UniValue & entry, const CTxDestination &dest)
{
    if (IsValidDestination(dest)) {
        entry.push_back(Pair("address", EncodeDestination(dest)));
    }
}
/**
 * List transactions based on the given criteria.
 *
 * @param  pwallet    The wallet.
 * @param  wtx        The wallet transaction.
 * @param  strAccount The account, if any, or "*" for all.
 * @param  nMinDepth  The minimum confirmation depth.
 * @param  fLong      Whether to include the JSON version of the transaction.
 * @param  ret        The UniValue into which the result is stored.
 * @param  filter     The "is mine" filter bool.
 */
void ListTransactions(CWallet* const pwallet, const CWalletTx& wtx, const std::string& strAccount, int nMinDepth, bool fLong, UniValue& ret, const isminefilter& filter)