Ticket 49246 - ns-slapd crashes in role cache creation
    
    Bug Description:  Using a nested filter for a filtered role can
                      cause a crash.  This was due to the way the filter
                      was being checked by the roles plugin.
    
    Fix Description:  Properly resurse over a filter.
    
    https://pagure.io/389-ds-base/issue/49246
    
    Reviewed by: firstyear & tbordaz(Thanks!!)