Fix WebSocket when running under a security manager

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1532506 13f79535-47bb-0310-9956-ffa450edef68
Fix Servlet 3.1 non-blocking when running with a security manager

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1532511 13f79535-47bb-0310-9956-ffa450edef68