Make the error messages clearer in sh_spec.py.

Print a FATAL error when the number of allowed failures is not what we
got.

test/sh_spec.py

@@ -895,21 +895,27 @@ def main(argv):
      f.write('\n')  # bash 'read' requires a newline

  if stats['num_failed'] == 0:
    #if stats['osh_num_passed'] == 0:
    #  print('*** Exit with status 2 because osh not tested', file=sys.stderr)
    #  return 2  # Change success to exit code 2 if we didn't run osh
    return 0

  allowed = opts.osh_failures_allowed
  all_count = stats['num_failed'] 
  osh_count = stats['osh_num_failed']
  if allowed == 0:
    log('')
    log('FATAL: %d tests failed (%d osh failures)', all_count, osh_count)
    log('')
  else:
    allowed = opts.osh_failures_allowed
    all_count = stats['num_failed'] 
    osh_count = stats['osh_num_failed']
    # If we got the allowed number of failures, exit 0.
    if allowed != 0 and allowed == all_count and all_count == osh_count:
      print('*** Got %d allowed osh failures, exit with status 0' % allowed,
          file=sys.stderr)
    # If we got EXACTLY the allowed number of failures, exit 0.
    if allowed == all_count and all_count == osh_count:
      log('note: Got %d allowed osh failures (exit with code 0)', allowed)
      return 0
    else:
      log('')
      log('FATAL: Got %d failures (%d osh failures), but %d are allowed',
          all_count, osh_count, allowed)
      log('')

    return 1
  return 1


if __name__ == '__main__':