add check for missing token mandatory key in test_mandatory_keys_in_spec

seems already implemented in sams_hub.py

test/test_sams_proxy.py

@@ -33,6 +33,8 @@ class TestSAMSHub(unittest.TestCase):
         , 'token': {'name': 'user'}},
       {'in': '/foo/bar', 'out': 'http://baz.foo'
         , 'token': {'value': 'user'}},
+      {'in': '/foo/bar', 'out': 'http://baz.foo'
+        , 'token': {'name': 'user', 'value': 'user'}},
       {'in': '/foo/bar', 'out': 'http://baz.foo'
         , 'session-passthrough': {}},
       {'in': '/foo/bar', 'out': 'http://baz.foo'