Exit create_vps.sh on first error

See https://open.greenhost.net/openappstack/openappstack/-/jobs/15079
for an example where the script fails but the CI job still continues

.gitlab/ci_scripts/create_vps.sh

 #!/usr/bin/env sh
 # Check if cluster directory was available from cache
-set -v
+
+set -ve
 
 if [ -d clusters/$HOSTNAME/secrets ]
 then