Don't crash when validating an empty file
Don't crash when validating an empty file

Fixes #807

marrero984/showoff,marrero984/showoff,marrero984/showoff,puppetlabs/showoff,puppetlabs/showoff,marrero984/showoff,puppetlabs/showoff,binford2k/showoff,binford2k/showoff,binford2k/showoff,binford2k/showoff,puppetlabs/showoff