addmultisigaddress creates an address respecting the setting, being unable to generate a specific type of address without also adding it to the wallet seems wrong.

I suppose in the future `addresstype` may be refactored to be wallet-specific, which would leave this non-wallet rpc call without an argument. Perhaps there should just be an optional parameter to set it.
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 2) {
        throw std::runtime_error(
            "sethdseed ( \"newkeypool\" \"seed\" )\n"
            "\nSet or generate a new HD wallet seed. Non-HD wallets will not be upgraded to being a HD wallet. Wallets that are already\n"
            "HD will have a new HD seed set so that new keys added to the keypool will be derived from this new seed.\n"
            "\nNote that you will need to MAKE A NEW BACKUP of your wallet after setting the HD wallet seed.\n"
            + HelpRequiringPassphrase(pwallet) +
            "\nArguments:\n"
            "1. \"newkeypool\"         (boolean, optional, default=true) Whether to flush old unused addresses, including change addresses, from the keypool and regenerate it.\n"
            "                             If true, the next address from getnewaddress and change address from getrawchangeaddress will be from this new seed.\n"
            "                             If false, addresses (including change addresses if the wallet already had HD Chain Split enabled) from the existing\n"
            "                             keypool will be used until it has been depleted.\n"
            "2. \"seed\"               (string, optional) The WIF private key to use as the new HD seed; if not provided a random seed will be used.\n"
            "                             The seed value can be retrieved using the dumpwallet command. It is the private key marked hdseed=1\n"
            "\nExamples:\n"
            + HelpExampleCli("sethdseed", "")
            + HelpExampleCli("sethdseed", "false")