fix merge error

Author: mr-c

cwltool/utils.py

@@ -6,6 +6,7 @@
 import platform
 import random
 import shutil
+import string
 import sys
 from functools import partial  # pylint: disable=unused-import
 from typing import (IO, Any, AnyStr, Callable,  # pylint: disable=unused-import
@@ -216,4 +217,4 @@ def random_outdir():  # type: () -> Text
     # compute this once and store it as a function attribute - each subsequent call will return the same value
     if not hasattr(random_outdir, 'outdir'):
         random_outdir.outdir = '/' + ''.join([random.choice(string.ascii_letters) for _ in range(6)])
-    return random_outdir.outdir
+    return random_outdir.outdir