Missing JavaDoc (last CheckStyle issue)

[Donnerbart]

There are just two classes which need a JavaDoc on the class level to get rid of all CheckStyle suppressions for this project. That's a nice low hanging fruit :)

hazelcast-wm/src/main/java/com/hazelcast/web/HazelcastHttpSession.java:34: Missing a Javadoc comment.
hazelcast-wm/src/main/java/com/hazelcast/web/WebDataSerializerHook.java:29: Missing a Javadoc comment.

If someone could write some wise words there we can delete this last suppression:

    <!-- Web -->
    <suppress checks="JavadocType" files="com/hazelcast/web/"/>