Remove now unneeded functional test

According to comment in this commit:
https://review.openstack.org/#/c/147136/ ,
since following functionality
https://github.com/openstack/heat/commit/f3f9d68fc13d192650f1e4dca484da2efa635a38
was merged, test test_create_config_prop_validation
has to be removed.

Change-Id: I27656529a7980d18a741d94f1740c0eb011e5d08
diff --git a/functional/test_instance_group.py b/functional/test_instance_group.py
index 9a79801..8478932 100644
--- a/functional/test_instance_group.py
+++ b/functional/test_instance_group.py
@@ -10,11 +10,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import copy
 import logging
-import yaml
-
-from heatclient import exc
 
 from heat_integrationtests.common import test
 
@@ -168,31 +164,6 @@
         stack = self.client.stacks.get(stack_identifier)
         self.assert_instance_count(stack, 4)
 
-    def test_create_config_prop_validation(self):
-        """Make sure that during a group create the instance
-        properties are validated. And an error causes the group to fail.
-        """
-        stack_name = self._stack_rand_name()
-
-        # add a property without a default and don't provide a value.
-        # we use this to make the instance fail on a property validation
-        # error.
-        broken = yaml.load(copy.copy(self.instance_template))
-        broken['parameters']['no_default'] = {'type': 'string'}
-        files = {'provider.yaml': yaml.dump(broken)}
-        env = {'resource_registry': {'AWS::EC2::Instance': 'provider.yaml'},
-               'parameters': {'size': 4,
-                              'image': self.conf.image_ref,
-                              'keyname': self.conf.keypair_name,
-                              'flavor': self.conf.instance_type}}
-
-        # now with static nested stack validation, this gets raised quickly.
-        excp = self.assertRaises(exc.HTTPBadRequest, self.client.stacks.create,
-                                 stack_name=stack_name, template=self.template,
-                                 files=files, disable_rollback=True,
-                                 parameters={}, environment=env)
-        self.assertIn('Property no_default not assigned', str(excp))
-
     def test_size_updates_work(self):
         files = {'provider.yaml': self.instance_template}
         env = {'resource_registry': {'AWS::EC2::Instance': 'provider.yaml'},