Fix for OPENAM-3064 The code now handles the case when there is no filtered roles retrieved. New unit tests has been introduced to improve the coverage around DSEE roles and filteredroles.

Fix for OPENAM-2787 - review: CR-2187 This one turned out to be an issue with the modifyRoleMembership implementation: instead of modifying the user entries to have the nsRoleDN attribute, it was incorrectly setting the member DNs on the role entry. New tests have been incorporated to cover this scenario.