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.
{
    
    CKey seed;                     
    CExtKey masterKey;             
    CExtKey accountKey;            
    CExtKey chainChildKey;         
    CExtKey childKey;              
    
    if (!GetKey(hdChain.seed_id, seed))
        throw std::runtime_error(std::string(__func__) + ": seed not found");
    masterKey.SetSeed(seed.begin(), seed.size());