Renaming files ignores file deletions

[amb007]

This chunk in export_commit (in the version used by ht-export-tool):

  for filename in removed:
    if fn_encoding:
      filename=filename.decode(fn_encoding).encode('utf8')
    filename=strip_leading_slash(filename)
    if filename==b'.hgsub':
      remove_gitmodules(ctx)
    wr(b'D %s' % filename)

  export_file_contents(ctx,man,added,hgtags,fn_encoding,plugins)
  export_file_contents(ctx,man,changed,hgtags,fn_encoding,plugins)

allows the export_file_contents to rename a file via a file_data_filter plugin, but then uses the original name if the file is removed in a later commit.

[frej]

There is no call to the file_data_filter for deleted files, that looks like an omission. Perhaps we could add a call and call the plugin with the file contents as None?