linstor: Use template's uuid if pool's downloadPath is null as resour…

[ghernadi]

Description

My colleague, @rp- is on vacation right now and we found a bug where the previously non-null VMTemplateStoragePoolVO#getLocalDownloadPath for some reason returns null in the recent versions of Cloudstack. This is my attempt to patch the issue, which worked in our test-setup.

Types of changes

• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] New feature (non-breaking change which adds functionality)
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] Enhancement (improves an existing feature and functionality)
• [ ] Cleanup (Code refactoring and cleanup, that may add test cases)
• [ ] build/CI
• [ ] test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• [ ] Major
• [x] Minor

Bug Severity

• [ ] BLOCKER
• [ ] Critical
• [ ] Major
• [x] Minor
• [ ] Trivial

Screenshots (if appropriate):

How Has This Been Tested?

The following scenario no longer works without this patch:

• Create a new VM (instance)
• Stop VM and make a snapshot of it
• Create a template from the just created snapshot
• Create a new VM from the new template

The last step causes the cloud-plugin-storage-volume-linstor to try to clone from cs-null instead of cs-${template_uuid}. cs-null obviously does not exist within LINSTOR itself, which causes an error.

How did you try to break this feature and the system with this change?