tempest: Allow to not run deprecated API tests

This change introduces the tempest option
[telemetry]/deprecated_api_enabled to not run
tests against the old API.

Change-Id: I66189111d795b88625fb4d41f853c848decccc05
diff --git a/ceilometer/tests/tempest/config.py b/ceilometer/tests/tempest/config.py
index 6df0ff4..3749b97 100644
--- a/ceilometer/tests/tempest/config.py
+++ b/ceilometer/tests/tempest/config.py
@@ -36,4 +36,8 @@
     cfg.BoolOpt('event_enabled',
                 default=True,
                 help="Runs Ceilometer event-related tests"),
+    cfg.BoolOpt('deprecated_api_enabled',
+                default=True,
+                help="Runs Ceilometer deprecated API tests"),
+
 ]