Clean up pylint errors in top-level files

Change-Id: Ida7cf1ff0cbf94ad82c7a75708c79ad7bb27f7fd

nova/wsgi.py

@@ -19,20 +19,16 @@
 
 """Utility methods for working with WSGI servers."""
 
-import os
 import sys
 
-from xml.dom import minidom
-
 import eventlet
 import eventlet.wsgi
 import greenlet
+from paste import deploy
 import routes.middleware
 import webob.dec
 import webob.exc
 
-from paste import deploy
-
 from nova import exception
 from nova import flags
 from nova import log as logging