On the log-addressing branch:  Fix the calculation of the revision
starting the next shard during FSFS upgrade.

* subversion/libsvn_fs_fs/fs_fs.c
  (upgrade_body): get my maths straight

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/log-addressing@1535667 13f79535-47bb-0310-9956-ffa450edef68