Re-run vendoring on packaging 16.4 (adding utils.py module, apparently omitted).

pkg_resources/_vendor/packaging/utils.py

+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import re
+
+
+_canonicalize_regex = re.compile(r"[-_.]+")
+
+
+def canonicalize_name(name):
+    # This is taken from PEP 503.
+    return _canonicalize_regex.sub("-", name).lower()