### 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

ListTransactions(pwallet, tx, "*", 0, true, transactions, filter);
        }
    }
    
    
    UniValue removed(UniValue::VARR);
    while (include_removed && paltindex && paltindex != pindex) {
        CBlock block;
        if (!ReadBlockFromDisk(block, paltindex, Params().GetConsensus())) {
            throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
        }
        for (const CTransactionRef& tx : block.vtx) {
            auto it = pwallet->mapWallet.find(tx->GetHash());
            if (it != pwallet->mapWallet.end()) {
                
                
                ListTransactions(pwallet, it->second, "*", -100000000, true, removed, filter);
            }
        }
        paltindex = paltindex->pprev;
    }
    CBlockIndex *pblockLast = chainActive[chainActive.Height() + 1 - target_confirms];
    uint256 lastblock = pblockLast ? pblockLast->GetBlockHash() : uint256();
    UniValue ret(UniValue::VOBJ);
    ret.push_back(Pair("transactions", transactions));
    if (include_removed) ret.push_back(Pair("removed", removed));
    ret.push_back(Pair("lastblock", lastblock.GetHex()));
    return ret;
}
UniValue gettransaction(const JSONRPCRequest& request)