Fix Qt 0.14.2->0.15.0 segfault if "total at least" is selected

A button was removed, so now button(1) is nullptr

Github-Pull: #11332
Rebased-From: cdaf3a1f9e
Tree-SHA512: 0a49bf4e9ab08e5869170c8a212da60c9a6b90c36427d788de384aa4be6d87bb5e00a21edf78eed34f81bbc554b6f15565bb9b493dafcbfe9d6f4664d7424d9d

src/qt/sendcoinsdialog.cpp

@@ -128,7 +128,7 @@ SendCoinsDialog::SendCoinsDialog(const PlatformStyle *_platformStyle, QWidget *p
     ui->groupFee->setId(ui->radioCustomFee, 1);
     ui->groupFee->button((int)std::max(0, std::min(1, settings.value("nFeeRadio").toInt())))->setChecked(true);
     ui->groupCustomFee->setId(ui->radioCustomPerKilobyte, 0);
-    ui->groupCustomFee->button((int)std::max(0, std::min(1, settings.value("nCustomFeeRadio").toInt())))->setChecked(true);
+    ui->groupCustomFee->button(0)->setChecked(true);
     ui->customFee->setValue(settings.value("nTransactionFee").toLongLong());
     ui->checkBoxMinimumFee->setChecked(settings.value("fPayOnlyMinFee").toBool());
     minimizeFeeSection(settings.value("fFeeSectionMinimized").toBool());