Adding 2 traffic based test cases.

1) test_udp_update_pool_healthmonitor_listener
   Traffic should PASS after updating any of LB's components.

2) test_hm_op_status_changed_as_expected_on_update
   Update health monitor with various combinations of:
   HTTP method, expected HTTP status codes and backend URL.
   Validate that members' operation status is getting into
   appropriate state on each update.

Change-Id: Ie80378ac1a96941eefa905fd6f49c8fa7e9c3692
diff --git a/octavia_tempest_plugin/common/constants.py b/octavia_tempest_plugin/common/constants.py
index 174589c..2910d40 100644
--- a/octavia_tempest_plugin/common/constants.py
+++ b/octavia_tempest_plugin/common/constants.py
@@ -139,6 +139,11 @@
 POST = 'POST'
 PUT = 'PUT'
 DELETE = 'DELETE'
+HEAD = 'HEAD'
+OPTIONS = 'OPTIONS'
+PATCH = 'PATCH'
+CONNECT = 'CONNECT'
+TRACE = 'TRACE'
 
 # HM Types
 HEALTH_MONITOR_PING = 'PING'