[Wallet] print hd masterkeyid in getwalletinfo

Zcash: modified for zip32

src/wallet/rpcwallet.cpp

@@ -2280,6 +2280,7 @@ UniValue getwalletinfo(const UniValue& params, bool fHelp)
             "  \"keypoolsize\": xxxx,        (numeric) how many new keys are pre-generated\n"
             "  \"unlocked_until\": ttt,      (numeric) the timestamp in seconds since epoch (midnight Jan 1 1970 GMT) that the wallet is unlocked for transfers, or 0 if the wallet is locked\n"
             "  \"paytxfee\": x.xxxx,         (numeric) the transaction fee configuration, set in " + CURRENCY_UNIT + "/kB\n"
+            "  \"seedfp\": \"uint256\",        (string) the BLAKE2b-256 hash of the HD seed\n"
             "}\n"
             "\nExamples:\n"
             + HelpExampleCli("getwalletinfo", "")
@@ -2299,6 +2300,9 @@ UniValue getwalletinfo(const UniValue& params, bool fHelp)
     if (pwalletMain->IsCrypted())
         obj.push_back(Pair("unlocked_until", nWalletUnlockTime));
     obj.push_back(Pair("paytxfee",      ValueFromAmount(payTxFee.GetFeePerK())));
+    uint256 seedFp = pwalletMain->GetHDChain().seedFp;
+    if (!seedFp.IsNull())
+         obj.push_back(Pair("seedfp", seedFp.GetHex()));
     return obj;
 }