Description of problem:
We're trying to remove PyXML from Fedora 18 due to it being dead upstream and having the dubious behaviour of replacing the python stdlib's xml module with its own code.  https://fedoraproject.org/wiki/User:Toshio/Remove_PyXML

I've taken a look at python-nova's use of PyXML and I think we can just remove the dep.  No documentation mentions a PyXML requirement.  The code uses xml.dom.minidom and xml.parsers.expat which are both present in the python stdlib and lxml which is in the python-lxml package.