Fix MultiLoctionResolver leak

- on resolve, was creating sub-locs; these weren’t being cleaned up
  on unmanage(loc) so BasicLocationRegistry.resolveForPeeking failed
Avoid repeated logging: rest api LocationResource
Avoid repeated logging: BasicLocationRegistry
Nginx rebind: fix for if nginx not running
PR #1405 review comments

- Move Entities.isManaged(Location) etc to Locations
- Adds javadoc to LocationPredicates.isChildOf and
  EntityPredicates.isChildOf
- Adds LocationPredicates.isDescendantOf
PR #1405: predicate input @Nullable
Merge pull request #1405 from aledsage/fix/MultiLocation-leak

Fix: MultiLocation leak