Fix uninitialized member in constructor. coverity CID 11886

git-svn-id: http://root.cern.ch/svn/root/trunk@35874 27541ba8-7e3a-0410-8455-c3a389f83636

graf2d/qt/inc/TQtApplication.h

@@ -44,7 +44,7 @@ protected:
 
 public:
 
-   TQtApplication() {};
+   TQtApplication() {fGUIThread=0;};
    TQtApplication(const char *appClassName, int &argc, char **argv);
    virtual ~TQtApplication();
    static bool Terminate();