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/os2/window.cpp

@@ -3038,11 +3038,7 @@ bool wxWindowOS2::HandleDestroy()
     // Delete our drop target if we've got one
     //
 #if wxUSE_DRAG_AND_DROP
-    if (m_dropTarget != NULL)
-    {
-        delete m_dropTarget;
-        m_dropTarget = NULL;
-    }
+    wxDELETE(m_dropTarget);
 #endif // wxUSE_DRAG_AND_DROP
 
     //