Change path for stacklight tests

Now all stacklight tests present in 'stacklight_tests/tests' dir
so replace path with actual one

Change-Id: Ic37711f94e355016f2175fdcb24e2cdeba607404
diff --git a/tcp_tests/tests/system/test_3rdparty_suites.py b/tcp_tests/tests/system/test_3rdparty_suites.py
index 78583af..0abb89b 100644
--- a/tcp_tests/tests/system/test_3rdparty_suites.py
+++ b/tcp_tests/tests/system/test_3rdparty_suites.py
@@ -59,7 +59,7 @@
         sl_actions.run_sl_functional_tests(
                 'cfg01',
                 '/root/stacklight-pytest/stacklight_tests/',
-                'tests/prometheus',
+                'tests',
                 'test_alerts.py',
                 junit_report_name='stacklight_report.xml')
         # Download report