Don't prompt with fingerprint when using --ca-certs
Don't prompt with fingerprint when using --ca-certs

The --ca-certs option suggests that the user already retrieved the CA by
other means (eg. out-of-band). Thus it is not necessary to print for
manual verification of the fingerprint.

This also keeps backwards compatibility with the previous CLI.

https://jira.mesosphere.com/browse/DCOS_OSS-4066

dcos/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli