On the fsfs-format7 branch: Improve pool usage during DAG node construction.
Forward the scratch / result pool parameters along the caller chain.

* subversion/libsvn_fs_fs/dag.h
  (svn_fs_fs__dag_dir_entry): distinguish between scratch and result pool

* subversion/libsvn_fs_fs/dag.c
  (svn_fs_fs__dag_dir_entry): update implementation
  (dir_entry_id_from_node): update caller


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1442081 13f79535-47bb-0310-9956-ffa450edef68