ClangCodeModel: Use clangd's include path

... rather than the one from the LLVM that Qt Creator was compiled
against.

Task-number: QTCREATORBUG-27120
Change-Id: I4f211345ed547cd13f0b0774b99bc0f199a9cd44
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangcodemodelplugin.cpp

@@ -86,7 +86,8 @@ void ClangCodeModelPlugin::generateCompilationDB()
             = QtConcurrent::run(&Internal::generateCompilationDB, projectInfo,
                                 projectInfo->buildRoot(), CompilationDbPurpose::Project,
                                 warningsConfig,
-                                optionsForProject(target->project(), warningsConfig));
+                                optionsForProject(target->project(), warningsConfig),
+                                FilePath());
     Core::ProgressManager::addTask(task, tr("Generating Compilation DB"), "generate compilation db");
     m_generatorWatcher.setFuture(task);
 }