Added a negative test for Signature Confirmation

git-svn-id: https://svn.apache.org/repos/asf/cxf/branches/wss4j2.0-port@1459233 13f79535-47bb-0310-9956-ffa450edef68
Minor change

git-svn-id: https://svn.apache.org/repos/asf/cxf/branches/wss4j2.0-port@1459234 13f79535-47bb-0310-9956-ffa450edef68