Fix SubmissionRunner ignoring errors while removing temporary directory with judge results

[rien]

This pull request removes the non-existing argument verbose: true from the FileUtils.remove_entry_secure method, as it causes this method to silently ignore errors.

The method FileUtils#remove_entry_secure has the following signature:

def remove_entry_secure(path, force = false)

The verbose: true argument is actually translated to a hash, causing the parameter force to be truthy. Any errors thrown while removing the unwanted files, are ignored because of the last line of the method:

  raise unless force

This was hiding errors in Dolos because of this bug (see the first two commits in: dodona-edu/dolos#1413).