Renamed Status to State

As we can see in the codebase, we have 3 "Status" enums which are
located at:

- watcher/objects/action.py
- watcher/objects/action_plan.py
- watcher/objects/audit.py

So I renamed them from "Status" to "State" to be consistent with
the DB schema.

Change-Id: If3d180c9daba6ae9083775ad6813aa4c21763dbf
Closes-Bug: #1522733

watcher/db/sqlalchemy/api.py

@@ -322,7 +322,7 @@ class Connection(api.BaseConnection):
             values['uuid'] = utils.generate_uuid()
 
         if values.get('state') is None:
-            values['state'] = audit_objects.AuditStatus.PENDING
+            values['state'] = audit_objects.State.PENDING
 
         audit = models.Audit()
         audit.update(values)