Fix for crash when quiting QGIS (ticket #5145)

Author: mhugent

src/app/qgisapp.cpp

@@ -673,6 +673,7 @@ QgisApp::~QgisApp()
   delete mMapTools.mMoveLabel;
   delete mMapTools.mRotateLabel;
   delete mMapTools.mChangeLabelProperties;
+  delete mMapTools.mOffsetCurve;
 
   delete mPythonUtils;