Print ctr error when ctr binary fails
Print ctr error when ctr binary fails

so that we do not get cryptic failures like "future change is not
possible"

Co-authored-by: Mario Nitchev <57ff50f6ddd5ceca6cfb80c4da981adc6ad05ef5@gmail.com>

cloudfoundry-incubator/guardian,cloudfoundry-incubator/guardian,cloudfoundry-incubator/guardian