Description of problem:
koan assumes default rpm queryformat

Version-Release number of selected component (if applicable):
0:2.0.3.1-3.el5.noarch

How reproducible:
always

Steps to Reproduce:
1. globaly modify rpm queryformat
2. run koan --replace-self  


Actual results:

exceptions.ValueError
invalid literal for float(): c
  File "/usr/lib/python2.4/site-packages/koan/app.py", line 215, in main
    k.run()
   File "/usr/lib/python2.4/site-packages/koan/app.py", line 334, in run
    self.replace()
   File "/usr/lib/python2.4/site-packages/koan/app.py", line 895, in replace
    return self.net_install(after_download)
   File "/usr/lib/python2.4/site-packages/koan/app.py", line 571, in net_install
    after_download(self, profile_data)
   File "/usr/lib/python2.4/site-packages/koan/app.py", line 804, in after_download
    (make, version, rest) = utils.os_release()
   File "/usr/lib/python2.4/site-packages/koan/utils.py", line 358, in os_release
    version = float(version[0])

Additional info:
FIX: in  /usr/lib/python2.4/site-packages/koan/utils.py", line 358 also use --queryformat