MirrorManager crawler patch

[Bruno Wolff III]

On Mon, Jul 20, 2009 at 01:27:11 -0400,
  Ricky Zhou <ricky at fedoraproject.org> wrote:
> 2) MirrorManager currently doesn't check timestamps, and the solution to
>    this isn't trivial, especially since with FTP, which returns
>    directory listing data as just the text of the output.  This is
>    almost impossible to parse accurately, especially when time zones are
>    involved, and when time zone data isn't even returned by FTP.

Maybe you could check a hash of the repomd.xml file? You shouldn't have to
track too many different hashes.