[MAJOR] ported appsession to use mempools v2

Also during this process, a bug was found in appsession_refresh().
It would not automatically requeue the task in the queue, so the
old sessions would not vanish.
diff --git a/src/haproxy.c b/src/haproxy.c
index c88bffc..7f5641c 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -667,12 +667,12 @@
 	pool_destroy(pool_requri);
 	pool_destroy2(pool2_task);
 	pool_destroy(pool_capture);
-	pool_destroy(pool_appsess);
+	pool_destroy2(pool2_appsess);
 	pool_destroy2(pool2_pendconn);
     
 	if (have_appsession) {
-		pool_destroy(apools.serverid);
-		pool_destroy(apools.sessid);
+		pool_destroy2(apools.serverid);
+		pool_destroy2(apools.sessid);
 	}
 } /* end deinit() */