bdutil's "-f" flag doesn't work for some confirmation prompts

[dennishuo]

The -f/--force flag is supposed to skip all confirmation prompts, but it doesn't correctly skip the prompts for running as root or for overwriting an existing config in generate_config.

[dennishuo]

This issue was originally reported on StackOverflow: http://stackoverflow.com/questions/29856918/how-to-force-bdutil-command-to-run-as-root