### 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

UniValue transactions(UniValue::VARR);
            if (it != mapTally.end())
            {
                for (const uint256& _item : (*it).second.txids)
                {
                    transactions.push_back(_item.GetHex());
                }
            }
            obj.push_back(Pair("txids", transactions));
            ret.push_back(obj);
        }
    }
    if (fByAccounts)
    {
        for (std::map<std::string, tallyitem>::iterator it = mapAccountTally.begin(); it != mapAccountTally.end(); ++it)
        {
            CAmount nAmount = (*it).second.nAmount;
            int nConf = (*it).second.nConf;
            UniValue obj(UniValue::VOBJ);
            if((*it).second.fIsWatchonly)
                obj.push_back(Pair("involvesWatchonly", true));
            obj.push_back(Pair("account",       (*it).first));
            obj.push_back(Pair("amount",        ValueFromAmount(nAmount)));
            obj.push_back(Pair("confirmations", (nConf == std::numeric_limits<int>::max() ? 0 : nConf)));
            ret.push_back(obj);
        }
    }
    return ret;
}
UniValue listreceivedbyaddress(const JSONRPCRequest& request)