Fix xmlrpc module selection for incomplete backport (issue2551010).

Author: roeger

roundup/anypy/xmlrpc_.py

@@ -1,7 +1,8 @@
 try:
     # Python 3+.
     from xmlrpc import client, server
-except ImportError:
+    server.SimpleXMLRPCDispatcher
+except (ImportError, AttributeError):
     # Python 2.
     import xmlrpclib as client
     import SimpleXMLRPCServer as server