message: Fix spendmany fromaccount
diff: @@ -3501,6 +3501,10 @@ UniValue spendmany(const UniValue& params, bool fHelp) {
  LOCK2(cs_main, pwalletMain->cs_wallet);
  + // Only account "" have sigma coins.
  + if (!params[0].isNull() && !params[0].get_str().empty())
  + throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Account has insufficient funds");
  +
  UniValue sendTo = params[1].get_obj();
  CWalletTx wtx;
  