Description of problem:
Local repositories are initialised twice when rhnplugin is enabled, which causes
yum clean all to fail.

Version-Release number of selected component (if applicable):
yum-rhn-plugin-0.5.3-6.el5_2.6

How reproducible:
Always (at least on this system)

Steps to Reproduce:
1. Add a local repo file to /etc/yum.repos.d
2. Run yum clean all
  
Actual results:
# yum clean all
Loading "security" plugin
Loading "rhnplugin" plugin

Repository munin_noarch is listed more than once in the configuration


Expected results:
# yum clean all
Loading "security" plugin
Loading "rhnplugin" plugin
Cleaning up Everything


Additional info:
Workaround: Change enabled to 0 in /etc/yum/pluginconf.d/rhnplugin.conf before
running yum clean.