修复es 知识库查询bug (#2848)

server/knowledge_base/kb_service/es_kb_service.py

@@ -221,6 +221,9 @@ class ESKBService(KBService):
                 "query": {
                     "term": {
                         "metadata.source.keyword": file_path
+                    },
+                    "term": {
+                        "_index": self.index_name
                     }
                 }
             }