Description of problem:
In fedora-development.repo, we have the line:
deltaurl=http://www.lesbg.com/jdieter/updates/development/$basearch

In the yum-presto plugin, there's the following code:
def config_hook(conduit):
    # Set up repository specific deltarpm url and mirrorlist
    config.RepoConf.deltaurl = config.UrlListOption()

Later, in postreposetup_hook, we try to access this configuration with:
    print repo.deltaurl
where repo is an active repository (we actually loop through all of them).

The result:
None for all active repositories (including development)

Version-Release number of selected component (if applicable):
yum-3.1.6-2.fc7

How reproducible:
Always