On the log-addressing branch:  Correct index structure doc.

* subversion/libsvn_fs_fs/structure-indexes
  (FNV checksum):  fix off-by-one in description

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/log-addressing@1535695 13f79535-47bb-0310-9956-ffa450edef68