protected ResourceInstance createResource(String versionId) {
    return createResource(Resource.Type.VersionDefinition,
        Collections.singletonMap(Resource.Type.VersionDefinition, versionId));
  }
Creates a version by directly POSTing the XML body.  Unfortunately the request processor
uses JSON, so an appropriate JSON structure must be made to get to the ResourceProvider.
@param body     the XML
@param headers  the headers
@param ui       the URI info
ambari-server/src/main/java/org/apache/ambari/server/api/services/VersionDefinitionService.java