call OnInit() from all samples to allow using standard command line options with all of them (patch 1623971)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@44354 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dataview/dataview.cpp

@@ -365,6 +365,9 @@ IMPLEMENT_APP  (MyApp)
 
 bool MyApp::OnInit(void)
 {
+    if ( !wxApp::OnInit() )
+        return false;
+
     MyFrame *frame = new MyFrame(NULL, wxT("wxDataViewCtrl feature test"), 10, 10, 800, 340);
     frame->Show(true);