Claim post requires a body

One of the claim's test scenario used to send `None` to the server. The
later failed to deserialize this body and the response returned 400.
This patch removes `None` from the test scenario since a body is
requires to created a claim to begin with.

Change-Id: If2c6acefc84fb2b7cc5b4a26e1784b74a1ae1e22
Closes-bug: #1383604

tests/functional/wsgi/v1_1/test_claims.py

@@ -87,7 +87,7 @@ class TestClaims(base.V1_1FunctionalTestBase):
 
     test_query_claim.tags = ['smoke', 'positive']
 
-    @ddt.data(None, {}, {"grace": 100})
+    @ddt.data({}, {"grace": 100})
     def test_claim_default_ttl(self, doc):
         """Create claim with default TTL and grace values."""
         params = {'limit': 1}