Fix some warnings about unused parameters

Change-Id: I4cd941beec8a8b2d35a5b1fce48dd12facae7154
Reviewed-by: hjk <hjk@qt.io>

src/plugins/cmakeprojectmanager/fileapidataextractor.cpp

@@ -698,6 +698,8 @@ FileApiQtcData generateFallbackData(const FilePath &topCmakeFile,
                                     const FilePath &buildDirectory,
                                     QString errorMessage)
 {
+    Q_UNUSED(buildDirectory)
+
     FileApiQtcData result;
 
     result.rootProjectNode.reset(new CMakeProjectNode{sourceDirectory});