Merge pull request #998 from jimfulton/fix-packaging-import-in-dist

fixed incomplete import of packaging.specifiers and packaging.version

setuptools/dist.py

@@ -14,7 +14,8 @@ from distutils.util import rfc822_escape
 
 import six
 from six.moves import map
-import packaging
+import packaging.specifiers
+import packaging.version
 
 from setuptools.depends import Require
 from setuptools import windows_support