WW-4227 Removes wrong class reference

git-svn-id: https://svn.apache.org/repos/asf/struts/struts2/trunk@1546515 13f79535-47bb-0310-9956-ffa450edef68
WW-4227 Temporally reverts changes related to SecurityGate to allow prepare new release without introducing new API

git-svn-id: https://svn.apache.org/repos/asf/struts/struts2/trunk@1546516 13f79535-47bb-0310-9956-ffa450edef68