OPENDJ-1242 (CR-5982) Enable dsconfig to generate doc for properties changed through subcommand options

No properties were output for access-log-filtering-criteria.
Problem was linked to how leaf definitions were computed: always check if current definition is a leaf and in that case add it to the leafs definitions list.

DSConfig.java:
Renamed addLeafChildren to addIfLeaf() + changed the logic to check the passed in definition.