message: print the attempted directory on failure
  Summary: It's useful to see where it checked and couldn't find the executable
diff: @@ -123,7 +123,7 @@ def run_pass(
  dir_name = dirname(dir_name)
  executable_path = join(dir_name, 'redex-all')
  if not isfile(executable_path) or not os.access(executable_path, os.X_OK):
  - sys.exit('redex-all is not found or is not executable')
  + sys.exit('redex-all is not found or is not executable: ' + executable_path)
  log('Running redex binary at ' + executable_path)
  args = [executable_path] + [
  