Move vendored packaging module into pkg_resources._vendor, restoring...

Move vendored packaging module into pkg_resources._vendor, restoring independence of pkg_resources from setuptools. Fixes #311.

pkg_resources/__init__.py

@@ -75,9 +75,9 @@ try:
 except ImportError:
     pass
 
-import setuptools._vendor.packaging.version
-import setuptools._vendor.packaging.specifiers
-packaging = setuptools._vendor.packaging
+import pkg_resources._vendor.packaging.version
+import pkg_resources._vendor.packaging.specifiers
+packaging = pkg_resources._vendor.packaging
 
 
 class PEP440Warning(RuntimeWarning):

setuptools/command/egg_info.py

@@ -15,8 +15,8 @@ try:
     import packaging.version
 except ImportError:
     # fallback to vendored version
-    import setuptools._vendor.packaging.version
-    packaging = setuptools._vendor.packaging
+    import pkg_resources._vendor.packaging.version
+    packaging = pkg_resources._vendor.packaging
 
 from setuptools import Command
 from setuptools.command.sdist import sdist

setuptools/dist.py

@@ -17,8 +17,8 @@ try:
     import packaging.version
 except ImportError:
     # fallback to vendored version
-    import setuptools._vendor.packaging.version
-    packaging = setuptools._vendor.packaging
+    import pkg_resources._vendor.packaging.version
+    packaging = pkg_resources._vendor.packaging
 
 from setuptools.depends import Require
 from setuptools.compat import basestring, PY2

setuptools/tests/test_resources.py

@@ -8,9 +8,9 @@ import tempfile
 import shutil
 from unittest import TestCase
 
-import setuptools._vendor.packaging.version
-import setuptools._vendor.packaging.specifiers
-packaging = setuptools._vendor.packaging
+import pkg_resources._vendor.packaging.version
+import pkg_resources._vendor.packaging.specifiers
+packaging = pkg_resources._vendor.packaging
 
 import pkg_resources
 from pkg_resources import (parse_requirements, VersionConflict, parse_version,