Update copyright based upon latest 2.0 version. The SDF version

should become the master...

doc/guide/release/copyright.sdf

@@ -11,7 +11,7 @@ H1: OpenLDAP Software Copyrights
 
 H2: OpenLDAP Copyright
 
-[[copyright]] 1998,1999 The OpenLDAP Foundation, Redwood City, California, USA
+[[copyright]] 1998-1999 The OpenLDAP Foundation, Redwood City, California, USA
 All rights reserved.
 
 Redistribution and use in source and binary forms are permitted only
@@ -19,6 +19,9 @@ as authorized by the OpenLDAP Public License.  A copy of this
 license is available at {{URL:http://www.OpenLDAP.org/}}
 or in file LICENSE in the top-level directory of the distribution.
 
+Individual files and/or contributed packages may be copyright by
+other parties and their use subject to additional restrictions.
+
 This work is derived from the University of Michigan LDAP v3.3
 distribution.  Information concerning is available at
 .{{URL:http://www.umich.edu/~dirsvcs/ldap/ldap.html}}.