Warning fixes found under hardest mode of OpenWatcom. Seems clean in Borland, MinGW and DMC.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@29684 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/thread/thread.cpp

@@ -47,7 +47,7 @@ class MyApp : public wxApp
 {
 public:
     MyApp();
-    virtual ~MyApp();
+    virtual ~MyApp(){};
 
     virtual bool OnInit();
 
@@ -358,10 +358,6 @@ MyApp::MyApp()
     m_waitingUntilAllDone = false;
 }
 
-MyApp::~MyApp()
-{
-}
-
 // `Main program' equivalent, creating windows and returning main app frame
 bool MyApp::OnInit()
 {