Don't include error.kw in the error response in the JSON server.

This can include a full exception which cannot be marshalled. This
value contains duplicate information and isn't used by the client.

ticket 905

ipaserver/rpcserver.py

@@ -423,7 +423,6 @@ class jsonserver(WSGIExecutioner):
                 code=error.errno,
                 message=error.strerror,
                 name=error.__class__.__name__,
-                kw=dict(error.kw),
             )
         response = dict(
             result=result,