ITS#8837 Fix pw-pbkdf2 manpage name to get it installed

contrib/slapd-modules/passwd/pbkdf2/slapo-pw-pbkdf2.5 → contrib/slapd-modules/passwd/pbkdf2/slapd-pw-pbkdf2.5

-.TH SLAPO-PW-PBKDF2 5 "RELEASEDATE" "OpenLDAP LDVERSION"
+.TH SLAPD-PW-PBKDF2 5 "RELEASEDATE" "OpenLDAP LDVERSION"
 .\" Copyright 2015-2020 The OpenLDAP Foundation All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
 .\" $OpenLDAP$
 .SH NAME
-slapo-pw-pbkdf2 \- PBKDF2 password module to slapd
+slapd-pw-pbkdf2 \- PBKDF2 password module to slapd
 .SH SYNOPSIS
 ETCDIR/slapd.conf
 .RS