ProjectDependencyGraph bug: in case of filtering, non-direct module links are lost

The FilteredProjectDependencyGraph is used to "narrow" reactor when constrained projects are used (ie use of -pl and alike of methods). The code was correct when transitive upstream or downstream in-project dependencies were asked, but in case of non-transitive ones the links were lost, if "intermediary" was removed from reactor.

In case of modules (A, B, C) and relationship A -> B -> C if active projects were only (A, C), the filtered links should result in (A -> C), unlike today, in A and C being "unrelated" that is simply no true.