BaseStorage: also ensure the target node of alias has 'node_id' field

ffstatus/basestorage.py

@@ -207,8 +207,12 @@ class BaseStorage(object):
                              alias_id, item_id)
                 continue
 
-            # merge data
+            # ensure both target and alias node have 'node_id' field set
+            if not 'node_id' in item:
+                item['node_id'] = item_id
             alias['node_id'] = alias_id
+
+            # merge data
             update = self.__merge_alias_node(item, alias)
             updated[item_id] = update
             logging.debug("Merged alias '%s' into '%s'.", alias_id, item_id)