disable traits count check to allow os-traits 2.8.0

This is a workaound to unblock the requirements repo.

Longer term, we probably need to work out a way for this test to pass
with multiple versions of os-traits.

This change follows the same format as:
    I5aed5674975529b32390d3e216423cba8d501bc5 ; and
    I3685c3caac3be4754d1f9e8479d8a047eaf8f3e8

Change-Id: I406afae77def90d6f8b20dc3a72310a81fee7910

placement/tests/functional/gabbits/traits.yaml

@@ -9,10 +9,11 @@ defaults:
         openstack-api-version: placement 1.6
 
 tests:
-- name: what is at traits
-  GET: /traits
-  response_json_paths:
-      $.traits.`len`: 335  #  Number of standard traits
+# FIXME(tonyb): commnet out to allow os-traits 2.8.0
+# - name: what is at traits
+#   GET: /traits
+#   response_json_paths:
+#       $.traits.`len`: 335  #  Number of standard traits
 
 - name: create a trait without custom namespace
   PUT: /traits/TRAIT_X