repodata changes

[Anders F Björklund]

I've added the additions for the new repodata format
to the 1.2 milestone, since it's needed for Fedora...

Fedora 11: --checksum=sha256
(changes in createrepo 0.9.7 with yum 3.2.22)

#331935 checksum type changed from SHA1 to SHA256

   This means that there is no SHA1 digest anymore,
   easiest was to add the new SHA256 digest as well

Fedora 10: --unique-md-filenames
(changes in createrepo 0.9.4 with yum 3.2.10)

#302453 subfiles are now using digest in filename

   This means that the filenames change for each update,
   and thus the old files wasn't being removed properly

Fedora 9 had some bugs with the yum repodata showing
the wrong file sizes, but didn't need Smart changes.

--anders

PS. It should still work OK with the old repodata format,
     that didn't require Yum to generate (createrepo 0.4)

     http://createrepo.baseurl.org/
     http://yum.baseurl.org/