Put test id in zk chroot path

In an effort to help debug leaked zk chroots add the test id to the
chroot path so that we can see which tests are leaking.

Change-Id: I27047ecfa69d59964ac9ad4a03941b9826099420
diff --git a/tests/unit/test_nodepool.py b/tests/unit/test_nodepool.py
index 0a55f9f..0f23c9e 100644
--- a/tests/unit/test_nodepool.py
+++ b/tests/unit/test_nodepool.py
@@ -29,7 +29,8 @@
     def setUp(self):
         super(BaseTestCase, self).setUp()
 
-        self.zk_chroot_fixture = self.useFixture(ChrootedKazooFixture())
+        self.zk_chroot_fixture = self.useFixture(
+            ChrootedKazooFixture(self.id()))
         self.zk_config = '%s:%s%s' % (
             self.zk_chroot_fixture.zookeeper_host,
             self.zk_chroot_fixture.zookeeper_port,