LevelDb include guard replaced with #pragma once

Summary: Replaced LevelDb include guards with #pragma once

Test Plan: make all check

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33939

port/port.h

@@ -7,8 +7,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
-#ifndef STORAGE_LEVELDB_PORT_PORT_H_
-#define STORAGE_LEVELDB_PORT_PORT_H_
+#pragma once
 
 #include <string>
 
@@ -19,4 +18,3 @@
 #include "port/port_posix.h"
 #endif
 
-#endif  // STORAGE_LEVELDB_PORT_PORT_H_

port/port_posix.h

@@ -9,8 +9,7 @@
 //
 // See port_example.h for documentation for the following types/functions.
 
-#ifndef STORAGE_LEVELDB_PORT_PORT_POSIX_H_
-#define STORAGE_LEVELDB_PORT_PORT_POSIX_H_
+#pragma once
 
 #undef PLATFORM_IS_LITTLE_ENDIAN
 #if defined(OS_MACOSX)
@@ -139,4 +138,3 @@ extern void InitOnce(OnceType* once, void (*initializer)());
 } // namespace port
 } // namespace rocksdb
 
-#endif  // STORAGE_LEVELDB_PORT_PORT_POSIX_H_