fixed client registration

  File "/usr/lib/python2.6/site-packages/spacewalk/server/apacheRequest.py", line 349, in response
    response = xmlrpclib.dumps(response, methodresponse = 1)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1132, in dumps
    data = m.dumps(params)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 677, in dumps
    dump(v, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 699, in __dump
    f(self, value, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 759, in dump_array
    dump(v, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 699, in __dump
    f(self, value, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 780, in dump_struct
    dump(v, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 699, in __dump
    f(self, value, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 703, in dump_nil
    raise TypeError, "cannot marshal None unless allow_none is enabled"
TypeError: cannot marshal None unless allow_none is enabled
Automatic commit of package [spacewalk-backend] release [2.2.17-1].