Remove Java 7 dependency that was missed in back-port

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1522491 13f79535-47bb-0310-9956-ffa450edef68
Ensure that only the web socket implementation classes are compiled with Java 7. This is done by making sure everything else is compiled first with Java 6.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1522492 13f79535-47bb-0310-9956-ffa450edef68