Add missing copyright header

Summary:
"examples/c_simple_example.c" did not have a proper copyright header.
Closes https://github.com/facebook/rocksdb/pull/1670

Differential Revision: D4327445

Pulled By: yiwu-arbug

fbshipit-source-id: a70389e

examples/c_simple_example.c

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>

examples/simple_example.cc

@@ -2,6 +2,7 @@
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree. An additional grant
 // of patent rights can be found in the PATENTS file in the same directory.
+
 #include <cstdio>
 #include <string>