Description of problem:

I got a complant about a el5 repo: 

>
> kevin-spamassassin-el/primary_db
> | 8.0 kB     00:00
> http://copr-be.cloud.fedoraproject.org/results/kevin/spamassassin-el/epel-5-i386/repodata/f4e8852a350249d7c87d91cf2bd40a839feed7e341436339e6c2f9e03dfb0fca-primary.sqlite.bz2:
> [Errno -3] Error performing checksum Trying other mirror. Error:
> failure:
> repodata/f4e8852a350249d7c87d91cf2bd40a839feed7e341436339e6c2f9e03dfb0
> fca-primary.sqlite.bz2 from kevin-spamassassin-el: [Errno 256] No
> more mirrors to try.

This is due to el5 having a really old yum and python-hashlib being
optional. If they have it installed, it works, if not it does not.
Perhaps copr could pass 'md5' for those repos? Or say people need
python-hashlib... 


We want to pass 
 "--checksum md5" to createrepo_c if target platform is el5.