Fixed tense consistency (used past) in statuses

In several places in Watcher, there are statuses which corresponds
to a status in the respective life cycle. There were used past tense
everywhere, except "SUCCESS" which was written in present tense.

So I searched for all the occurences of this state, and replaced them
with their past tense form.

Change-Id: Ic41def96d1a608da06a1e394e24704d4f06ab32a
Closes-Bug: #1520276

watcher/tests/objects/test_audit.py

@@ -93,12 +93,12 @@ class TestAuditObject(base.DbTestCase):
             with mock.patch.object(self.dbapi, 'update_audit',
                                    autospec=True) as mock_update_audit:
                 audit = objects.Audit.get_by_uuid(self.context, uuid)
-                audit.state = 'SUCCESS'
+                audit.state = 'SUCCEEDED'
                 audit.save()
 
                 mock_get_audit.assert_called_once_with(self.context, uuid)
                 mock_update_audit.assert_called_once_with(
-                    uuid, {'state': 'SUCCESS'})
+                    uuid, {'state': 'SUCCEEDED'})
                 self.assertEqual(self.context, audit._context)
 
     def test_refresh(self):