CORD-2312 unit tests for vsg syncsteps

Change-Id: I745bc90b0c27a28a430282611c79677569ec978d
(cherry picked from commit 3fa6a7ab207a3ef38a659ec37b5cc6f0d312416f)
diff --git a/xos/unittest.cfg b/xos/unittest.cfg
index a5bdb18..71be7ca 100644
--- a/xos/unittest.cfg
+++ b/xos/unittest.cfg
@@ -2,3 +2,4 @@
 plugins=nose2-plugins.exclude
 code-directories=synchronizer
                  model_policies
+                 steps