Extend FSFS-stats tool to also count the file nodes that are added
without history.  That way, we can tell the efficiency of our text
delta implementation.

* tools/server-side/fsfs-stats.c
  (fs_fs_t): add members for added nodes
  (add_change): record nodes without delta base as well
  (read_noderev): update caller
  (print_stats): update stats output

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1519283 13f79535-47bb-0310-9956-ffa450edef68