Update functional test definitions

Remove trusty-icehouse test combo from gate, leaving trusty-mitaka
if/where it exists.

Change-Id: Id14d83ae5a2dcb31267270ac5dacb2015708c756

tests/gate-basic-trusty-icehouse

-#!/usr/bin/env python
-#
-# Copyright 2016 Canonical Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#  http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-"""Amulet tests on a basic ceilometer deployment on trusty-icehouse."""
-
-from basic_deployment import CeilometerBasicDeployment
-
-if __name__ == '__main__':
-    deployment = CeilometerBasicDeployment(series='trusty')
-    deployment.run_tests()