Use nullptr here

messageviewer/src/viewer/pluginloader.h

@@ -85,7 +85,7 @@ private:
 public:
     virtual ~PluginLoader()
     {
-        mSelf = 0;
+        mSelf = nullptr;
     }
 
     /** Returns the single instance of this loader. */

messageviewer/src/viewer/stl_util.h

@@ -40,7 +40,7 @@ struct DeleteAndSetToZero {
     void operator()(const T *&t)
     {
         delete t;
-        t = 0;
+        t = nullptr;
     }
 };