Y2k copyright update

clients/Makefile.in

clients/mail500/mail500.m4

clients/mail500/main.c

clients/tools/ldapdelete.c

clients/tools/ldapmodify.c

clients/tools/ldapmodrdn.c

clients/tools/ldappasswd.c

clients/tools/ldapsearch.c

clients/ud/auth.c

clients/ud/edit.c

clients/ud/find.c

clients/ud/globals.c

clients/ud/group.c

clients/ud/help.c

clients/ud/main.c

clients/ud/mod.c

clients/ud/print.c

clients/ud/string_to_key.c

clients/ud/ud.h

clients/ud/util.c