Print detailed log of download job failure

[nebula-bots]

Your Environments (required)

How To Reproduce(required)

1. execute the download job twice in the same space, the first time successful, the second time failed
   
2. checking the storage logs, there is no clear reason for the failure, I need to execute the command manually to know the reason for the failure
   
   

Expected behavior

1. when download job Failed， Print detailed failure logs
2. If the download file already exists, should delete it first before executing the download operation

[shanlai]

3.3 rc checked