[Backport] Add missing GIL scope to single shot timer destructor

- provided by Florian Link

(cherry picked from commit MeVisLab/pythonqt@89983a0)

Author: mrbean-bremen

src/PythonQtStdDecorators.cpp

@@ -432,11 +432,19 @@ PythonQtSingleShotTimer::PythonQtSingleShotTimer(int msec, const PythonQtObjectP
   connect(this, SIGNAL(timeout()), this, SLOT(slotTimeout()));
 }
 
+PythonQtSingleShotTimer::~PythonQtSingleShotTimer()
+{
+  PYTHONQT_GIL_SCOPE
+  _callable = nullptr;
+}
+
 void PythonQtSingleShotTimer::slotTimeout()
 {
   if (_callable) {
+    PYTHONQT_GIL_SCOPE
     _callable.call();
   }
   // delete ourself
   deleteLater();
 }
+

src/PythonQtStdDecorators.h

@@ -124,6 +124,7 @@ class PythonQtSingleShotTimer : public QTimer
   Q_OBJECT
 public:
   PythonQtSingleShotTimer(int msec, const PythonQtObjectPtr& callable);
+  ~PythonQtSingleShotTimer() override;
 
 public Q_SLOTS :
   void slotTimeout();