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.
Reviewed by: firstyear & tbordaz(Thanks!!)
(cherry picked from commit 54e4fca35899550e0c25b25e7f7c756302d258ce)