Update xmltojson.xml

Updated the policy xmltojson.xml to fix the deployment issue. Here is the error description:
Import failed to /v1/organizations/arch123/apis?action=import&name=xmltojson with status 400:
{
  "code" : "steps.xml2json.EitherOptionOrFormat",
  "message" : "XMLToJSON[{0}]: Either Options or Format must be specified",
  "contexts" : [ ]
}