### 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

"4. minconf               (numeric, optional, default=1) Only use funds with at least this many confirmations.\n"
            "5. \"comment\"           (string, optional) A comment used to store what the transaction is for. \n"
            "                                     This is not part of the transaction, just kept in your wallet.\n"
            "6. \"comment_to\"        (string, optional) An optional comment to store the name of the person or organization \n"
            "                                     to which you're sending the transaction. This is not part of the transaction, \n"
            "                                     it is just kept in your wallet.\n"
            "\nResult:\n"
            "\"txid\"                 (string) The transaction id.\n"
            "\nExamples:\n"
            "\nSend 0.01 " + CURRENCY_UNIT + " from the default account to the address, must have at least 1 confirmation\n"
            + HelpExampleCli("sendfrom", "\"\" \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\" 0.01") +
            "\nSend 0.01 from the tabby account to the given address, funds must have at least 6 confirmations\n"
            + HelpExampleCli("sendfrom", "\"tabby\" \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\" 0.01 6 \"donation\" \"seans outpost\"") +
            "\nAs a json rpc call\n"
            + HelpExampleRpc("sendfrom", "\"tabby\", \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\", 0.01, 6, \"donation\", \"seans outpost\"")
        );
    ObserveSafeMode();
    LOCK2(cs_main, pwallet->cs_wallet);
    std::string strAccount = AccountFromValue(request.params[0]);
    CTxDestination dest = DecodeDestination(request.params[1].get_str());
    if (!IsValidDestination(dest)) {
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Bitcoin address");
    }
    CAmount nAmount = AmountFromValue(request.params[2]);
    if (nAmount <= 0)
        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
    int nMinDepth = 1;
    if (!request.params[3].isNull())
        nMinDepth = request.params[3].get_int();
    CWalletTx wtx;