GUI: Write PSBTs to file with binary mode

Github-Pull: #bitcoin-core/gui#188
Rebased-From: cc3971c9ff

src/qt/psbtoperationsdialog.cpp

@@ -145,7 +145,7 @@ void PSBTOperationsDialog::saveTransaction() {
     if (filename.isEmpty()) {
         return;
     }
-    std::ofstream out(filename.toLocal8Bit().data());
+    std::ofstream out(filename.toLocal8Bit().data(), std::ofstream::out | std::ofstream::binary);
     out << ssTx.str();
     out.close();
     showStatus(tr("PSBT saved to disk."), StatusLevel::INFO);

src/qt/sendcoinsdialog.cpp

@@ -427,7 +427,7 @@ void SendCoinsDialog::on_sendButton_clicked()
             if (filename.isEmpty()) {
                 return;
             }
-            std::ofstream out(filename.toLocal8Bit().data());
+            std::ofstream out(filename.toLocal8Bit().data(), std::ofstream::out | std::ofstream::binary);
             out << ssTx.str();
             out.close();
             Q_EMIT message(tr("PSBT saved"), "PSBT saved to disk", CClientUIInterface::MSG_INFORMATION);