Set verbosity of FPM to match Hammer's log level

[langston-barrett]

Hammer outputs FPM's error message when packaging fails. Unfortunately, this log doesn't always have enough information. It would be great for debugging purposes if Hammer set FPM's --log option:

    --log LEVEL                   Set the log level. Values: error, warn, info, debug.

to match its own:

      --log-level string    one of debug, info, warn, error, or fatal (default "info")