Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/dataview.cpp

@@ -4349,11 +4349,7 @@ void wxDataViewCtrl::OnInternalIdle()
 
 bool wxDataViewCtrl::AssociateModel( wxDataViewModel *model )
 {
-    if ( m_internal )
-    {
-        delete m_internal;
-        m_internal = NULL;
-    }
+    wxDELETE(m_internal);
 
     if (!wxDataViewCtrlBase::AssociateModel( model ))
         return false;