def vet_output(*args)
      last_output = git_output(*args).strip
      logger.info(last_output) unless last_output.empty?
      if last_output.downcase =~ /^(error|fatal):/
        raise GitError, "Git exited zero but an error was detected in output."
      end
      true
    end
def vet_output(*args)
      last_output = git_output(*args).strip
      logger.info(last_output) unless last_output.empty?
      if last_output.downcase =~ /^(error|fatal):/
        raise GitError, "Git exited zero but an error was detected in output."
      end
      true
    end
msysgit on Windows exits zero even when checkout|reset|fetch fails so we
 need to scan the output for error or fatal messages. it does no harm to do
 the same on Linux even though the exit code works properly there.

 @param [String|Array] args to execute

 @return [TrueClass] always true