jetty-client expires can null exchange while generator still using it

The testExpires() test can fail because the connection expires in the time between the expires() method the timer runs that nulls out the exchange spooks the HttpParser when calling the notification methods (that use the now null exchange).

28-Jan-2009 02:40:35 Running org.mortbay.jetty.client.ExpireTest
28-Jan-2009 02:40:35 2009-01-28 02:40:35.883::INFO: jetty-7.0-SNAPSHOT
28-Jan-2009 02:40:35 2009-01-28 02:40:35.887::INFO: Started SelectChannelConnector@localhost:44291
28-Jan-2009 02:40:35 2009-01-28 02:40:35.887::INFO: Starting test on http://localhost:44291/
28-Jan-2009 02:40:57 2009-01-28 02:40:57.967::WARN: handle failed
28-Jan-2009 02:40:57 java.lang.NullPointerException
28-Jan-2009 02:40:57 at org.mortbay.jetty.client.HttpConnection$Handler.headerComplete(HttpConnection.java:510)
28-Jan-2009 02:40:57 at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:540)
28-Jan-2009 02:40:57 at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:214)
28-Jan-2009 02:40:57 at org.mortbay.jetty.client.HttpConnection.handle(HttpConnection.java:274)
28-Jan-2009 02:40:57 at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:421)
28-Jan-2009 02:40:57 at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:521)
28-Jan-2009 02:41:02 2009-01-28 02:41:02.048::INFO: waiting 5s for test to complete (max 30s)
28-Jan-2009 02:41:07 2009-01-28 02:41:07.051::INFO: waiting 5s for test to complete (max 30s)
28-Jan-2009 02:41:12 2009-01-28 02:41:12.054::INFO: waiting 5s for test to complete (max 30s)
28-Jan-2009 02:41:17 2009-01-28 02:41:17.057::INFO: waiting 5s for test to complete (max 30s)
28-Jan-2009 02:41:22 2009-01-28 02:41:22.059::INFO: waiting 5s for test to complete (max 30s)
28-Jan-2009 02:41:27 2009-01-28 02:41:27.061::INFO: waiting 5s for test to complete (max 30s)
28-Jan-2009 02:41:32 Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 56.304 sec <<< FAILURE!