6882654: Remove dependency on java.util.concurrent from KeepAlive
implementaion
Webrev:
http://cr.openjdk.java.net/~chegar/6882654/webrev.0/webrev/
The HTTP keep alive implementation has unnecessary dependencies on
java.util.concurrent classes.
KeepAliveCache subclasses ConcurrentHashMap even though all its methods
are synchronized, except run with synchronizes on the this object before
attempting to access and of the classes data.
KeepAliveStreamCleaner subclasses LinkedBlockingQueue, but we can easily
rewrite it since it only uses a simple timed poll.
-Chris.
