budget: fix an unused variable warning

This also fixups b9b14bc7 for the case
where the consumption range is different from consumed budget or engaged
budget (for exemple when we have only engaged movements on a given node)

bt5/erp5_budget/DocumentTemplateItem/portal_components/document.erp5.NodeBudgetVariation.py

@@ -134,7 +134,7 @@ class NodeBudgetVariation(BudgetVariation):
       consumption_dict = budget_line.getConsumedBudgetDict()
     else:
       consumption_dict = budget_line.getEngagedBudgetDict()
-    for consumed_budget_key in budget_line.getConsumedBudgetDict().keys():
+    for consumed_budget_key in consumption_dict.keys():
       for item in consumed_budget_key:
         if item.startswith(prefix):
           used_node_item_set.add(item)