Reduce height of frame in DND sample

Instead of moving the frame up every time to be able to reach the
dragging section at the bottom, change the sizer proportion of the log
control in the middle to reduce the frame's height.

samples/dnd/dnd.cpp

@@ -1050,7 +1050,7 @@ DnDFrame::DnDFrame()
     wxBoxSizer *sizer = new wxBoxSizer( wxVERTICAL );
     sizer->Add(sizer_top, 1, wxEXPAND );
 #if wxUSE_LOG
-    sizer->Add(m_ctrlLog, 2, wxEXPAND);
+    sizer->Add(m_ctrlLog, 1, wxEXPAND);
     sizer->SetItemMinSize(m_ctrlLog, 450, 200);
 #endif // wxUSE_LOG
     sizer->AddSpacer(50);