Update all affected files' copyright year to 2018

Because the related PR/commits are merged in 2018...

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4976)

doc/man3/UI_UTIL_read_pw.pod

diff --git a/doc/man3/UI_UTIL_read_pw.pod b/doc/man3/UI_UTIL_read_pw.pod
index 5535576..a59cc4f 100644
--- a/doc/man3/UI_UTIL_read_pw.pod
+++ b/doc/man3/UI_UTIL_read_pw.pod
@@ -62,7 +62,7 @@
 
 =head1 COPYRIGHT
 
-Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2001-2018 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