rocksdb: put `#pragma once` before `#ifdef`

Summary: Work around upstream bug with modules: https://bugs.llvm.org/show_bug.cgi?id=39184.

Reviewed By: yiwu-arbug

Differential Revision: D10209569

fbshipit-source-id: 696853a02a3869e9c33d0e61168ad4b0436fa3c0

include/rocksdb/ldb_tool.h

@@ -2,8 +2,8 @@
 //  This source code is licensed under both the GPLv2 (found in the
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
-#ifndef ROCKSDB_LITE
 #pragma once
+#ifndef ROCKSDB_LITE
 #include <string>
 #include <vector>
 #include "rocksdb/db.h"

include/rocksdb/sst_file_writer.h

@@ -3,10 +3,10 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
-#ifndef ROCKSDB_LITE
-
 #pragma once
 
+#ifndef ROCKSDB_LITE
+
 #include <memory>
 #include <string>
 

utilities/redis/redis_list_exception.h

@@ -5,8 +5,8 @@
  * Copyright 2013 Facebook
  */
 
-#ifndef ROCKSDB_LITE
 #pragma once
+#ifndef ROCKSDB_LITE
 #include <exception>
 
 namespace rocksdb {