Description of problem:

Trying to switch host to maintenance fails if there are finished transfers.

Error from engine UI:

    Error while executing action: Cannot switch Host host3 to Maintenance mode.
    Image transfer is in progress for the following (1) disks:

    3649d84b-6f35-4314-900a-5e8024e3905c

    Please wait for the operations to complete and try again.

Database state:

engine=# select command_id,phase,disk_id from image_transfers;
              command_id              | phase |               disk_id                
--------------------------------------+-------+--------------------------------------
 ac4f6304-bec1-45eb-8d20-aaa82d077236 |     9 | 3649d84b-6f35-4314-900a-5e8024e3905c
 fa495abf-6c0f-4846-b316-f0b37c1d2606 |     9 | 3649d84b-6f35-4314-900a-5e8024e3905c
 f2fc212b-b557-42f6-bcdc-ddce7f8d63cb |     9 | 3649d84b-6f35-4314-900a-5e8024e3905c
 619e1e15-adbb-46e0-9b1e-c5c42f2887aa |     9 | 3649d84b-6f35-4314-900a-5e8024e3905c
(4 rows)


Version-Release number of selected component (if applicable):
Software Version:4.4.8.3-0.0.master.20210801143636.git475a2e196e0.el8

How reproducible:
Always

Steps to Reproduce:
1. Perform image transfer (upload or download, from UI or from API)
2. Try to move host to maintenance
Expected:Host move to mainatainance
Actual:
User needs to wait about 15 minutes until all image transfers are deletedfrom the database.

Actual results:
Validation fails, host does not move to maintenance

Expected results:
Host move to maintenance

Additional info:
This is another regression introduced in 4.4.7.