For large commits that contain deletions, fetch_all_changes dominates the commit performance because it uses an O(n^2) to eliminate sub-path changes to deleted nodes.
For large commits that contain deletions, fetch_all_changes
dominates the commit performance because it uses an O(n^2)
to eliminate sub-path changes to deleted nodes.

Since switching to an O(n log n) implementation is non-trivial,
the next best thing is to minimize the operations within the
inner loop.

* subversion/libsvn_fs_fs/fs_fs.c
  (fetch_all_changes): tune

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1340874 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion