OAK-1143: [scala] Repository init throws "illegal cyclic reference involving class ChangeDispatcher"
Remove dependency on NodeStore from ChangeDispatcher. ChangeDispatcher does not poll for external changes anymore.

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1540692 13f79535-47bb-0310-9956-ffa450edef68