Nexus 2.11.x routing fixes

The RoutingFilteringIT almost never passed on me locally. While fixing it, found and fixed another problem: the endless cycle while deleting repo root (causing endless `/.nexus/trash/.nexus/attributes/.nexus/attributes..` deep files that ultimately made operation fail due to OS path length limit.

CI
http://bamboo.s/browse/NX-OSSF306
Suggest `excludesFilter` or something similar is a better name for this option. I keep getting confused as to whether the filter is supposed to be used to exclude or include files from the current operation :)