### 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("listaddressgroupings", "")
            + HelpExampleRpc("listaddressgroupings", "")
        );
    ObserveSafeMode();
    LOCK2(cs_main, pwallet->cs_wallet);
    UniValue jsonGroupings(UniValue::VARR);
    std::map<CTxDestination, CAmount> balances = pwallet->GetAddressBalances();
    for (const std::set<CTxDestination>& grouping : pwallet->GetAddressGroupings()) {
        UniValue jsonGrouping(UniValue::VARR);
        for (const CTxDestination& address : grouping)
        {
            UniValue addressInfo(UniValue::VARR);
            addressInfo.push_back(EncodeDestination(address));
            addressInfo.push_back(ValueFromAmount(balances[address]));
            {
                if (pwallet->mapAddressBook.find(address) != pwallet->mapAddressBook.end()) {
                    addressInfo.push_back(pwallet->mapAddressBook.find(address)->second.name);
                }
            }
            jsonGrouping.push_back(addressInfo);
        }
        jsonGroupings.push_back(jsonGrouping);
    }
    return jsonGroupings;
}
UniValue signmessage(const JSONRPCRequest& request)