use services decorator to enable telemetry test

switch to use services decorator as opposed to testtools.skipIf

Change-Id: I0e87fc0f76a4c9cfac308d685230da59787a3e7b
diff --git a/tempest/api/telemetry/test_telemetry_notification_api.py b/tempest/api/telemetry/test_telemetry_notification_api.py
index 7057910..bf1e046 100644
--- a/tempest/api/telemetry/test_telemetry_notification_api.py
+++ b/tempest/api/telemetry/test_telemetry_notification_api.py
@@ -29,8 +29,7 @@
                                     "is disabled")
 
     @test.idempotent_id('d7f8c1c8-d470-4731-8604-315d3956caad')
-    @testtools.skipIf(not CONF.service_available.nova,
-                      "Nova is not available.")
+    @test.services('compute')
     def test_check_nova_notification(self):
 
         body = self.create_server()