allow skip horizon haproxy test

The horizon haproxy test currently fails because the connection
between haproxy and horizon is currently broken.  It should be fixed
by https://review.opendev.org/c/openstack/tripleo-heat-templates/+/883129
or similar.

Until it is fixed, add an option to skip haproxy tests for specified
services (in this case, horizon)

Change-Id: I598dfaafdd8e3e2b8e29b9463c5f4e1287ea68b9

novajoin_tempest_plugin/config.py

@@ -55,6 +55,9 @@ NovajoinGroup = [
     cfg.ListOpt('tripleo_exclude_cert_tags',
                 default=[],
                 help='List of tags to exclude from certmonger checks'),
+    cfg.ListOpt('tripleo_exclude_haproxy_services',
+                default=[],
+                help='List of services to exclude from haproxy checks'),
     cfg.StrOpt('tripleo_undercloud',
                default='undercloud',
                help='Undercloud short host name'),

novajoin_tempest_plugin/tests/scenario/test_tripleo_tls.py

@@ -80,6 +80,9 @@ class TripleOTLSTest(novajoin_manager.NovajoinScenarioTest):
             services = self.parse_haproxy_cfg(haproxy)
 
             for tag, params in services.items():
+                if tag in CONF.novajoin.tripleo_exclude_haproxy_services:
+                    print("Skipping {service}".format(service=tag))
+                    continue
                 print("*** Testing {service}".format(service=tag))
                 for param in params:
                     print(param)