Don't leak BeautifierPluginPrivate on shutdown

Properly delete QtcProcess used for version on shutdown.

Change-Id: I325a267ba5bb28a82158d9c50802955804713be0
Reviewed-by: hjk <hjk@qt.io>

src/plugins/beautifier/beautifierplugin.cpp

@@ -133,6 +133,13 @@ void BeautifierPlugin::extensionsInitialized()
     dd = new BeautifierPluginPrivate;
 }
 
+ExtensionSystem::IPlugin::ShutdownFlag BeautifierPlugin::aboutToShutdown()
+{
+    delete dd;
+    dd = nullptr;
+    return SynchronousShutdown;
+}
+
 BeautifierPluginPrivate::BeautifierPluginPrivate()
 {
     updateActions();

src/plugins/beautifier/beautifierplugin.h

@@ -49,6 +49,7 @@ public:
 private:
     bool initialize(const QStringList &arguments, QString *errorString) override;
     void extensionsInitialized() override;
+    ShutdownFlag aboutToShutdown() override;
 };
 
 } // namespace Internal