Fix imports and linter findings

* add back more missing things

awx/main/dispatch/worker/base.py

@@ -4,7 +4,6 @@
 import os
 import logging
 import signal
-import sys
 import time
 
 from django import db

awx/main/management/commands/run_dispatcher.py

@@ -3,7 +3,9 @@
 import logging
 import logging.config
 import yaml
+import copy
 
+from django.conf import settings
 from django.core.management.base import BaseCommand, CommandError
 from django.core.cache import cache as django_cache
 from django.db import connection