Description of problem:
After upgrading to latest rawhide (from rawhide of a few weeks ago)
yum-fastestmirror breaks yum. The following message is displayed:

[ifoox@localhost ~]$ yum info pydev
Loading "fastestmirror" plugin
Loading "installonlyn" plugin
Loading mirror speeds from cached hostfile
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.main(sys.argv[1:])
  File "/usr/share/yum-cli/yummain.py", line 82, in main
    base.getOptionsConfig(args)
  File "/usr/share/yum-cli/cli.py", line 159, in getOptionsConfig
    (opts, self.cmds) = self.optparser.setupYumConfig()
  File "/usr/share/yum-cli/cli.py", line 1134, in setupYumConfig
    self.base.setupProgessCallbacks()
  File "/usr/share/yum-cli/output.py", line 322, in setupProgessCallbacks
    self.repos.setProgressBar(TextMeter(fo=sys.stdout))
  File "/usr/lib/python2.5/site-packages/yum/__init__.py", line 497, in <lambda>
    repos = property(fget=lambda self: self._getRepos(),
  File "/usr/lib/python2.5/site-packages/yum/__init__.py", line 348, in _getRepos
    self.plugins.run('postreposetup')
  File "/usr/lib/python2.5/site-packages/yum/plugins.py", line 163, in run
    func(conduitcls(self, self.base, conf, **kwargs))
  File "/usr/lib/yum-plugins/fastestmirror.py", line 83, in postreposetup_hook
    repo.urls = repomirrors[str(repo)]
AttributeError: can't set attribute


Version-Release number of selected component (if applicable):
yum-fastestmirror-1.1.2-1.fc7 
yum-3.1.7-1.fc7.noarch


How reproducible:
Always.

Steps to Reproduce:
1. Update to latest rawhide with yum-fastestmirror installed.
2. Run any yum command.
3. Witness breakage.
4. rpm -e yum-fastestmirror
5. Run any yum command
6. Witness bliss, albeit slowly.
  
Actual results:
Yum working.

Expected results:
Yum broken.

Additional info:
Cleaning cache and running either as normal user or su doesn't make a difference.