Copy components without parent_product when duplicating templates

issue11854
review418561003
(grafted from 699d42badcf0aed4fbe232d0e401e04ddad6bab6)

--HG--
branch : 6.0

product.py

@@ -44,7 +44,7 @@ class Template(metaclass=PoolMeta):
             to_copy = []
             for template, new_template in zip(templates, new_templates):
                 to_copy.extend(
-                    c for c in template.components if not c.product)
+                    c for c in template.components if not c.parent_product)
                 old2new[template.id] = new_template.id
             if to_copy:
                 Component.copy(to_copy, {