[skip e2e] Remove duplicated copyright (milvus-io#15073)

Signed-off-by: yudong.cai <yudong.cai@zilliz.com>

Author: cydrain

internal/core/src/indexbuilder/index_c.h

@@ -9,17 +9,6 @@
 // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 // or implied. See the License for the specific language governing permissions and limitations under the License
 
-// Copyright (C) 2019-2020 Zilliz. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
-// with the License. You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software distributed under the License
-// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
-// or implied. See the License for the specific language governing permissions and limitations under the License
-
 #pragma once
 
 #ifdef __cplusplus