CopySupport: Simplify manage_delObjects.

These variables are only used when they evaluate as true, so it is
pointless work to replace them with empty lists.

product/ERP5Type/CopySupport.py

@@ -212,9 +212,7 @@ class CopyContainer:
 
       The objects specified in 'ids' get deleted.
       """
-      if ids is None: ids = []
-      if uids is None: uids = []
-      if len(ids) > 0:
+      if ids:
         # Use default method
         return ObjectManager.manage_delObjects(self, ids, REQUEST)
       if not uids: