Disable test on Python 2.

changelog.d/1753.change.rst

 ``attr:`` now extracts variables through rudimentary examination of the AST,
-thereby supporting modules with third-party imports.  If examining the AST
+thereby supporting modules with third-party imports. If examining the AST
 fails to find the variable, ``attr:`` falls back to the old behavior of
-importing the module.
+importing the module. Works on Python 3 only.

setuptools/tests/test_config.py

@@ -10,6 +10,7 @@ from mock import patch
 from setuptools.dist import Distribution, _Distribution
 from setuptools.config import ConfigHandler, read_configuration
 from setuptools.extern.six.moves import configparser
+from setuptools.extern import six
 from . import py2_only, py3_only
 from .textwrap import DALS
 
@@ -310,6 +311,10 @@ class TestMetadata:
         with get_dist(tmpdir) as dist:
             assert dist.metadata.version == '2016.11.26'
 
+        if six.PY2:
+            # static version loading is unsupported on Python 2
+            return
+
         config.write(
             '[metadata]\n'
             'version = attr: fake_package.subpkg_b.mod.VERSION\n'