Allow test_playbook to run long

We've added several more ansible runs to this job, so it's naturally
going to run longer.  It's been timing out in the gate, so give it
more time.

Change-Id: Id9b2db6009ebe8473d4d452287192a559d999c5e
diff --git a/tests/unit/test_v3.py b/tests/unit/test_v3.py
index e36c8f6..f019ead 100755
--- a/tests/unit/test_v3.py
+++ b/tests/unit/test_v3.py
@@ -2033,6 +2033,8 @@
     tenant_config_file = 'config/ansible/main.yaml'
 
     def test_playbook(self):
+        # This test runs a bit long and needs extra time.
+        self.wait_timeout = 120
         # Keep the jobdir around so we can inspect contents if an
         # assert fails.
         self.executor_server.keep_jobdir = True