Fix for DIRSERVER-1961 :
- the transformation of an EmptyEvaluator into a BaseLevelScopeEvaluator is not anymore done
- the removeObjectClass() method has been fixed to not keep a more selective node than necessary.

git-svn-id: https://svn.apache.org/repos/asf/directory/apacheds/trunk@1572064 13f79535-47bb-0310-9956-ffa450edef68