Fixed an error when trying to cancel a token


Conflicts:
	rt/ws/security/src/main/java/org/apache/cxf/ws/security/policy/interceptors/STSInvoker.java

git-svn-id: https://svn.apache.org/repos/asf/cxf/branches/2.7.x-fixes@1533424 13f79535-47bb-0310-9956-ffa450edef68