MaaS 3.1 beta3 "enlist deployed machines" feature fails during commission

[Ben Huntley]

Following instructions from section "How to update hardware information for a deployed machine" in the MaaS 3.1 beta 3 documentation (https://maas.io/docs/snap/3.1/ui/whats-new-in-maas) fails when deployed enlisted machine is commissioned using `./maas-run-scripts report-results`, likely on all Ubuntu OS flavors.

MaaS region server is running MAAS 3.1.0~beta3 on Ubuntu 20.04, installed from Deb. Rack controller is also running MAAS 3.1.0~beta3 on Ubuntu 20.04. Host being enlisted/comissioned is running Ubuntu 18.04.6.

Failure occurs when I attempt to update hardware information for enlisted deployed machine, using the following code snippet from documentation:
```
wget http://$MAAS_IP:5240/MAAS/maas-run-scripts
chmod 755 maas-run-scripts
./maas-run-scripts report-results --config $(hostname)-creds.yaml
```

Failure message as reported in the MaaS UI Commissioning log stderr, "50-maas-01-commissioning":
```
Failed to read /tmp/tmpht98ki46/resources.json: [Errno 2] No such file or directory: '/tmp/tmpht98ki46/resources.json'
```

Prior to this failure, "40-maas-01-machine-resources" succeeds but stderr log for Commissioning script "40-maas-01-machine-resources" shows message that it could not stat the resources.json file.

Appears this can be resolved by modifying "40-maas-01-machine-resources" script to add `touch $MAAS_RESOURCES_FILE` before "40-maas-01-machine-resources" script attempts the stat command.

[Alberto Donato (ack)]

> Appears this can be resolved by modifying "40-maas-01-machine-resources" script to add `touch $MAAS_RESOURCES_FILE` before "40-maas-01-machine-resources" script attempts the stat command.

Indeed, this is actually fixed in master at 11875e832, and will be included in the next beta.