On the fsx-id branch:  Replace instances of svn_fs_x__dag_get_id
with one of the new ID getters on the DAG node.

* subversion/libsvn_fs_x/tree.c
  (make_path_mutable): Directly ask for the noderev ID.
  (svn_fs_x__node_id): Use the new DAG API to return the FS API level IDs.
  (merge): Simplify using the noderev IDs directly.
  (copy_helper,
   stringify_node,
   verify_node): Switch to using noderev IDs.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx-id@1645657 13f79535-47bb-0310-9956-ffa450edef68