On the fsfs-format7 branch:  Fix index access code.  When reading
an index header from an existing stream, make sure we read from
the beginning of the index file and not from some random position.

* subversion/libsvn_fs_fs/index.c
  (get_l2p_header_body,
   get_p2l_page_info): reset stream before reading the header

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1446858 13f79535-47bb-0310-9956-ffa450edef68