On the fsfs-format7 branch: Minor packing code fixes.

* subversion/libsvn_fs_fs/pack.c
  (auto_pad_block): Unused entries shall contain ZERO sub-elements
  (select_block_entries): typo in comment


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1476639 13f79535-47bb-0310-9956-ffa450edef68