Add assert to make sure the temp file could be opened successfully.

src/core/Config.cpp

@@ -108,6 +108,8 @@ void Config::createTempFileInstance()
 {
     Q_ASSERT(!m_instance);
     QTemporaryFile* tmpFile = new QTemporaryFile(qApp);
-    tmpFile->open();
+    bool openResult = tmpFile->open();
+    Q_ASSERT(openResult);
+    Q_UNUSED(openResult);
     m_instance = new Config(tmpFile->fileName(), tmpFile);
 }

src/format/KeePass2XmlWriter.cpp

@@ -176,6 +176,7 @@ void KeePass2XmlWriter::writeBinaries()
 
             qint64 bytesWritten = compressor.write(i.key());
             Q_ASSERT(bytesWritten == i.key().size());
+            Q_UNUSED(bytesWritten);
             compressor.close();
 
             buffer.seek(0);