Use wxTextEntry::Clear() in wxOwnerDrawnComboBox::Clear()

This seems more natural than calling SetValue(wxEmptyString).

No real changes.

src/generic/odcombo.cpp

@@ -991,9 +991,7 @@ void wxOwnerDrawnComboBox::DoClear()
 
     GetVListBoxComboPopup()->Clear();
 
-    // NB: This really needs to be SetValue() instead of ChangeValue(),
-    //     as wxTextEntry API expects an event to be sent.
-    SetValue(wxEmptyString);
+    wxTextEntry::Clear();
 }
 
 void wxOwnerDrawnComboBox::Clear()