Avoid NPE on shutdown if application isn't using WebSocket.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1551483 13f79535-47bb-0310-9956-ffa450edef68
Avoid expected warning

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1551485 13f79535-47bb-0310-9956-ffa450edef68