Respect chroot in getEphemerals API

// manually create /foo path using zkcli for example
ZooKeeper zoo = new ZooKeeper("127.0.0.1/foo", 1000, event -> {});
zoo.create("/bar", "baz".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
List<String> ephemerals = zoo.getEphemerals();
System.out.println(ephemerals.toString());
// expected [/bar], actual [/foo/bar]