bosh-cli: deploy/int ignored ((xyz)) and didn't prompt for missing variable

I placed some ((xyz)) variables in a deployment manifest and expected bosh deploy manifest.yml and bosh int manifest.yml to fail and complain the variables hadn’t been provided.

Instead, they appeared in the manifest unmodified.

I’m aware of --var-errs flag; but perhaps it should be the default to fail on missing variables? This would help new users “fail fast” when not providing important variables; rather than booting up a system only to eventually debug and find ((xyz)) is a meaningless/erroneous input value.