Stop adding ServiceAvailable group option

Service available group already exists.Therefore we don't need to
register this group here again.

Change-Id: I2096ed1f69a1f70fbf248fee5fded94e3caca6c6
Closes-Bug: #1621036

watcher_tempest_plugin/config.py

@@ -17,11 +17,7 @@
 from oslo_config import cfg
 
 
-service_available_group = cfg.OptGroup(name="service_available",
-                                       title="Available OpenStack Services")
-
-ServiceAvailableGroup = [
-    cfg.BoolOpt("watcher",
-                default=True,
-                help="Whether or not watcher is expected to be available"),
-]
+service_option = cfg.BoolOpt("watcher",
+                             default=True,
+                             help="Whether or not watcher is expected to be "
+                                  "available")

watcher_tempest_plugin/plugin.py

@@ -13,7 +13,6 @@
 
 import os
 
-from tempest import config
 from tempest.test_discover import plugins
 
 from watcher_tempest_plugin import config as watcher_config
@@ -28,9 +27,8 @@ class WatcherTempestPlugin(plugins.TempestPlugin):
         return full_test_dir, base_path
 
     def register_opts(self, conf):
-        config.register_opt_group(
-            conf, watcher_config.service_available_group,
-            watcher_config.ServiceAvailableGroup)
+        conf.register_opt(watcher_config.service_option,
+                          group='service_available')
 
     def get_opt_lists(self):
-        return []
+        return [('service_available', [watcher_config.service_option])]