Drop unused fake class

It was a left-over from removal of ceilometer datasource[1].

[1] da23fdc621

Change-Id: I17ef33d6f70e2cc601add721661347d0bf210008

watcher/tests/decision_engine/model/faker_cluster_and_metrics.py

@@ -182,9 +182,3 @@ class FakeGnocchiMetrics(object):
         instance_disk_util['INSTANCE_8'] = 25
         instance_disk_util['INSTANCE_9'] = 25
         return instance_disk_util[str(resource.uuid)]
-
-
-# TODO(lpetrut): consider dropping Ceilometer support, it was deprecated
-# in Ocata.
-class FakeCeilometerMetrics(FakeGnocchiMetrics):
-    pass