Add copyright to manpages

Reviewed-by: Richard Levitte <levitte@openssl.org>

doc/ssl/SSL_rstate_string.pod

diff --git a/doc/ssl/SSL_rstate_string.pod b/doc/ssl/SSL_rstate_string.pod
index 7309483..88804c8 100644
--- a/doc/ssl/SSL_rstate_string.pod
+++ b/doc/ssl/SSL_rstate_string.pod
@@ -57,3 +57,14 @@
 L<ssl(3)>
 
 =cut
+
+=head1 COPYRIGHT
+
+Copyright 2001-2016 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
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut