On the log-addressing branch:  Create the phys-to-log index as well.
It will be used by packing and verification in later commits.

We only need to populate the extra index whenever we write to the
proto-rev file.

* subversion/libsvn_fs_fs/fs_fs.c
  (write_revision_zero): make the p2l index file part of the r0 template
                         in log addressing mode

* subversion/libsvn_fs_fs/transaction.c
  (store_p2l_index_entry): new index entry writer utility similar to
                           what we already have for l2p
  (rep_write_contents_close,
   write_hash_rep,
   write_hash_delta_rep,
   write_final_rev,
   write_final_changed_path_info): add p2l entries after writing to proto-rev
  (commit_body): transform the proto-index into the final index


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/log-addressing@1512232 13f79535-47bb-0310-9956-ffa450edef68