One of WorkQueue methods is called in the TaskArchiverPoller in Tier-0 WMAgent
In a replay testing the 2.1.5 T0 release (WMAgent 1.2.4.patch3 release) I observed the following error in the TaskArchiver logs:
```
2019-07-25 17:02:08,297:140059098547968:INFO:BaseWorkerThread:TaskArchiverPoller took 0.035 secs to execute
2019-07-25 17:02:08,300:140059098547968:DEBUG:LogDB:LogDB delete request, res=None
2019-07-25 17:06:08,595:140059098547968:DEBUG:LogDB:LogDB delete request, res=None
2019-07-25 17:06:08,596:140059098547968:INFO:TaskArchiverPoller:Polling for finished subscriptions
2019-07-25 17:06:08,600:140059098547968:INFO:TaskArchiverPoller:Finished subscriptions updated
2019-07-25 17:06:08,625:140059098547968:INFO:TaskArchiverPoller:Found 15 candidate workflows for completing:
2019-07-25 17:06:08,629:140059098547968:INFO:TaskArchiverPoller:There are 0 requests in ['force-complete', 'aborted'] status in central couch.
2019-07-25 17:06:08,630:140059098547968:ERROR:TaskArchiverPoller:we will try again when remote couch server comes back
'NoneType' object has no attribute 'killWMBSWorkflows'
2019-07-25 17:06:08,630:140059098547968:INFO:BaseWorkerThread:TaskArchiverPoller took 0.034 secs to execute
```
Refactoring the TaskArchiverPoller.py caused the `self.workQueue.killWMBSWorkflows(reqNames)` to be called:
https://github.com/dmwm/WMCore/commit/0f531f6826d1115e03267f4f55360fa7ef5e0911#diff-748e5dcfaf8a48d0e9774b3066780e42L197
even though T0 config.py configures workqueue = false.
diff --git a/src/python/WMComponent/TaskArchiver/TaskArchiverPoller.py b/src/python/WMComponent/TaskArchiver/TaskArchiverPoller.py
index efecfb925..0a623808e 100644
--- a/src/python/WMComponent/TaskArchiver/TaskArchiverPoller.py
+++ b/src/python/WMComponent/TaskArchiver/TaskArchiverPoller.py
@@ -193,7 +193,8 @@ class TaskArchiverPoller(BaseWorkerThread):
             statusList = [statusList]
         reqNames = self.centralCouchDBWriter.getRequestByStatus(statusList)
         logging.info("There are %d requests in %s status in central couch.", len(reqNames), statusList)
-        self.workQueue.killWMBSWorkflows(reqNames)
+        if self.workQueue is not None:
+            self.workQueue.killWMBSWorkflows(reqNames)
         return reqNames
 
     def completeTasks(self, finishedwfs):
['src/python/WMComponent/TaskArchiver/TaskArchiverPoller.py']