Restore setuptools import, falsely identified as an unused import by linter.

setuptools/package_index.py

@@ -17,6 +17,7 @@ except ImportError:
 from setuptools.extern import six
 from setuptools.extern.six.moves import urllib, http_client, configparser, map
 
+import setuptools
 from pkg_resources import (
     CHECKOUT_DIST, Distribution, BINARY_DIST, normalize_path, SOURCE_DIST,
     Environment, find_distributions, safe_name, safe_version,
@@ -47,7 +48,7 @@ __all__ = [
 _SOCKET_TIMEOUT = 15
 
 _tmpl = "setuptools/{setuptools.__version__} Python-urllib/{py_major}"
-user_agent = _tmpl.format(py_major=sys.version[:3], **globals())
+user_agent = _tmpl.format(py_major=sys.version[:3], setuptools=setuptools)
 
 
 def parse_requirement_arg(spec):