templates: Explicitly use v2019.1 for the first stage NFS
Our main LAVA jobs have two stages:
- boot a utility system via NFS whose only responsibility is to flash the real image to be tested on the SD card
- boot from the newly-written SD card
Currently the first stage is picked up from a server location that is maintained separatedly from the rest of the system. The version in the URLs of the artifacts matches the release that will be loaded, not the one used to build the artifacts: in fact, all of the current first stage use artifacts built from the ancient 18.12 release. This is not an issue because what we are actullay interested in testing here is the second stage (the actual NFS artifacts use different jobs).
However, this means that the hardlinks on the server side have to be set up every time we branch, and it's not obvious what we are actually using for the first stage.
This commit explicitly loads the v2019.1 NFS artifacts for the first stage instead, so the job definition is in full control and does not rely on some server state.
Test job here: https://lava.collabora.co.uk/scheduler/job/2151745