Rename core fixtures to match the drivetrain component names

The following changes:
  common_services_deployed -> core_deployed
  sl_deployed -> stacklight_deployed

Change-Id: I6e505d2ef96053b19b2d43b0214f5a30f71ae8ea
diff --git a/tcp_tests/tests/system/test_pipeline_deploy.py b/tcp_tests/tests/system/test_pipeline_deploy.py
index 1d2e79f..c98db38 100644
--- a/tcp_tests/tests/system/test_pipeline_deploy.py
+++ b/tcp_tests/tests/system/test_pipeline_deploy.py
@@ -27,7 +27,7 @@
 
     @pytest.mark.fail_snapshot
     def test_pipeline(self, show_step, underlay,
-                      common_services_deployed, salt_deployed):
+                      core_deployed, salt_deployed):
         """Runner for Juniper contrail-tests
 
         Scenario: