Fix the build

Despite the name, fileUrl is already a QByteArray encoded URL here.

thumbnail/thumbnail.cpp

@@ -735,7 +735,7 @@ bool ThumbnailProtocol::createSubThumbnail(QImage& thumbnail, const QString& fil
                 // to the cache for future access.
                 if (thumbnailfile.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
                     QFileInfo fi(filePath);
-                    thumbnail.setText(QStringLiteral("Thumb::URI"), QString::fromUtf8(fileUrl.toEncoded()));
+                    thumbnail.setText(QStringLiteral("Thumb::URI"), QString::fromUtf8(fileUrl));
                     thumbnail.setText(QStringLiteral("Thumb::MTime"), QString::number(fi.lastModified().toSecsSinceEpoch()));
                     thumbnail.setText(QStringLiteral("Thumb::Size"), QString::number(fi.size()));