Fix repository loader bug that mishandled zero-length files.
Fix repository loader bug that mishandled zero-length files.

* subversion/libsvn_repos/load.c
  (struct parse_baton, struct revision_baton, struct node_baton): Move
    to the top of the file.
  (parse_content_block): Handle the zero-length file case.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion