Implemented base + moved plugins & service conf

In this changeset, I implemented the main logic although this is
mainly a shameful copy/paste of Nova's blueprint
https://blueprints.launchpad.net/nova/+spec/centralize-config-options

Partially Implements: blueprint centralise-config-opts

Change-Id: Ib645ad5da5c706336bb6ac37e85b027d05665c32

watcher/tests/cmd/test_db_manage.py

@@ -54,7 +54,7 @@ class TestDBManageRunApp(base.TestCase):
         dbmanage.main()
         self.assertEqual(1, m_func.call_count)
         m_prepare_service.assert_called_once_with(
-            ["watcher-db-manage", self.expected])
+            ["watcher-db-manage", self.expected], cfg.CONF)
 
 
 class TestDBManageRunCommand(base.TestCase):

watcher/tests/conf/test_list_opts.py

@@ -17,7 +17,8 @@
 import mock
 from stevedore import extension
 
-from watcher import opts
+from watcher.conf import opts
+from watcher.conf import plugins
 from watcher.tests import base
 from watcher.tests.decision_engine import fake_strategies
 
@@ -26,10 +27,10 @@ class TestListOpts(base.TestCase):
     def setUp(self):
         super(TestListOpts, self).setUp()
         self.base_sections = [
-            'api', 'watcher_decision_engine', 'watcher_applier',
-            'watcher_planner', 'nova_client', 'glance_client',
-            'cinder_client', 'ceilometer_client', 'neutron_client',
-            'watcher_clients_auth']
+            'DEFAULT', 'api', 'database', 'watcher_decision_engine',
+            'watcher_applier', 'watcher_planner', 'nova_client',
+            'glance_client', 'cinder_client', 'ceilometer_client',
+            'neutron_client', 'watcher_clients_auth']
         self.opt_sections = list(dict(opts.list_opts()).keys())
 
     def test_run_list_opts(self):
@@ -135,10 +136,10 @@ class TestPlugins(base.TestCase):
 
         with mock.patch.object(extension, "ExtensionManager") as m_ext_manager:
             with mock.patch.object(
-                opts, "_show_plugins_ascii_table"
+                plugins, "_show_plugins_ascii_table"
             ) as m_show:
                 m_ext_manager.side_effect = m_list_available
-                opts.show_plugins()
+                plugins.show_plugins()
                 m_show.assert_called_once_with(
                     [('watcher_strategies.strategy_1', 'strategy_1',
                       'watcher.tests.decision_engine.'

watcher/tests/conf_fixture.py

@@ -20,7 +20,7 @@ from oslo_config import cfg
 from watcher.common import config
 
 CONF = cfg.CONF
-CONF.import_opt('host', 'watcher.common.service')
+CONF.import_opt('host', 'watcher.conf.service')
 CONF.import_opt('connection', 'oslo_db.options', group='database')
 CONF.import_opt('sqlite_synchronous', 'oslo_db.options', group='database')