Update copyright year

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6145)
diff --git a/test/verify_extra_test.c b/test/verify_extra_test.c
index 5d46542..d9d1498 100644
--- a/test/verify_extra_test.c
+++ b/test/verify_extra_test.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2017 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy