Code review comment for lp:~stefanor/ibid/rfc-plugin-330864

Exception when downloading RFC index:
  File "/home/mgorven/lp/stefanor/ibid/rfc-plugin-330864/ibid/utils.py", line
86, in cacheable_download
    os.path.rename(downloadfile, cachefile)
AttributeError: 'module' object has no attribute 'rename'

Search results should preferably be returned on a single line. This may
require removing some information like the date.