Add comment and link back to justification.

--HG--
extra : rebase_source : e6f4e62a87e24933c8821fdef141d194b90874d3

ez_setup.py

@@ -100,8 +100,12 @@ def _do_download(version, download_base, to_dir, download_delay):
                                       to_dir, download_delay)
         _build_egg(egg, tarball, to_dir)
     sys.path.insert(0, egg)
+
+    # Remove previously-imported pkg_resources if present (see
+    # https://bitbucket.org/pypa/setuptools/pull-request/7/ for details).
     if 'pkg_resources' in sys.modules:
         del sys.modules['pkg_resources']
+
     import setuptools
     setuptools.bootstrap_install_from = egg