[BB-4387] When provisioning an App Server and security group checks fail, state is left in New
This fixes an issue where, if something failed while checking security group definitions on OpenStack, the machine state would be left in New; the user would only be able to tell the process failed in the UI by looking through the logs.
Now, the machine state is set to error.
Related issues
Testing
./manage.py test instance.tests.models.test_openedx_appserver.OpenEdXAppServerTestCase.test_provision_security_group_check_failed