Bug 1958911

Description of problem
======================
Given I have a template
  And I exported that template to the export_domain in my data-center
  And I deleted the template from the storage domain it was created in
When I try to import the template from the export_domain
Then the import task transaction rolls back while the template remains in a status 'locked' and the import task is stuck

Version-Release number of selected component (if applicable)
============================================================
ovirt-engine-4.4.6.7-0.1.el8ev.noarch

How reproducible
================
100% when running QE network team's 'import_export suite'

Steps to Reproduce
==================
1. Create a VM
2. Create networks and attach to a single host in the cluster
3. Create vnics for the VM with the created vnic-profiles pointing to the networks
4. Create a template from the created VM.
5. Export both template and VM to the export_domain in the data-center.
6. Remove the VM and the template from the storage domain in which they were created.
7. Import the exported VM from the export_domain twice (each time by a different name).
8. Import the exported template from the export_domain twice (each time by a different name).

Actual results
==============
Template import tasks in UI are stuck while engine.log reports the import failed due to a transaction rollback. both templates are 'locked'.

Expected results
================
Templates are imported.

Additional info
===============
* These tasks stay stuck even after the ovirt-engine service is restarted.