On the fsfs-format7 branch:  Add a new internal API function to
determine the number of items we need to copy per rev to pack files,

* subversion/libsvn_fs_fs/index.h
  (svn_fs_fs__l2p_get_max_ids): declare new function

* subversion/libsvn_fs_fs/index.c
  (svn_fs_fs__l2p_get_max_ids): implement new function


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1438436 13f79535-47bb-0310-9956-ffa450edef68