Warning on the logs even when the job Clean Temporary Directory runs successfully

Issue Summary

The Clean Temporary Directory job successfully deletes the files but the logs show a warning. This does not happen when you run the job manually.

Steps to Reproduce

1. Configure a Confluence instance;
2. Start Confluence;
3. Head to General Configuration > Scheduled Jobs;
4. Next to Back Up Confluence, select Run (this will generate a .zip file in the <confluence-home>/temp directory);
5. Go to <confluence-home>/temp and note that the zip file for the back up is there;
6. Wait until the time set for the job to run (4:20 am by default);
   Note: Because Confluence backup is set to remain on the folder for 24h, you may have to wait until the next day or the zip won't be deleted. Unless you're affected by this bug.

Expected Results

1. The zip file is successfully removed from the directory;
2. There is no error on the logs.

Actual Results

1. The zip file is successfully removed from the directory;
2. The logs show this warning:

   2020-07-29 04:22:05,659 WARN [Caesium-1-1] [impl.schedule.caesium.JobRunnerWrapper] runJob Scheduled job webhooks.history.daily.cleanup.runner#webhooks.history.daily.cleanup.job completed unsuccessfully with response JobRunnerResponse[runOutcome=FAILED,message='IllegalStateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here']

Workaround

Since the job is working, the only workaround, for now, is to ignore the warnings on the logs.