mkcloud: Increase default compute node memory
mkcloud: Increase default compute node memory

With 2 GB, services on the compute node are running from time to time
OOM.

SUSE-Cloud/automation,gosipyan/automation,SUSE-Cloud/automation,aspiers/automation,aspiers/automation,SUSE-Cloud/automation,SUSE-Cloud/automation,gosipyan/automation,gosipyan/automation,vmoravec/automation,vmoravec/automation,aspiers/automation,vmoravec/automation,gosipyan/automation,aspiers/automation,vmoravec/automation