Make horizon check optional

Change-Id: I40fd6b00584925001f2672b8e1b4d679781fcc9f
diff --git a/tcp_tests/settings_oslo.py b/tcp_tests/settings_oslo.py
index 6773901..c0418c4 100644
--- a/tcp_tests/settings_oslo.py
+++ b/tcp_tests/settings_oslo.py
@@ -208,6 +208,8 @@
            help="", default=False),
     ct.Cfg('openstack_keystone_endpoint', ct.String(),
            help="", default=''),
+    ct.Cfg('horizon_check', ct.Boolean(),
+           help="", default=True),
 ]
 
 opencontrail_opts = [