On the fsfs-format7 branch: eliminate a seek() operation

* subversion/libsvn_fs_fs/index.c
  (packed_stream_open): the first read access will seek to the desired
                        offset, i.e. no need to seek() just after fopen().

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1476628 13f79535-47bb-0310-9956-ffa450edef68